Two factions of registered Democrats in Montgomery County will begin holding their endorsing conventions tonight, signaling the onset of what in the past has been traditional open season between political brothers.

One group, the Democratic Coalition, will continue its endorsement sessions for several evenings during the next few weeks.

The other group, Montgomery Democrats, will begin its endorsement convention June 5.

The two Democratic groups emerged this year as a result of longstanding arguments within the party on methods and procedures for endorsing and electing Democratic candidates in Montgomery County.

Political endorsements are believed to be helpful in the September primary elections, by showing that one candidate is preferred over another by party regulars.

Within Montgomery County, seats up for election this year include U.S. Congress, Montgomery County executive, all seven seats on the county council, six state senate seats and 43 state delegate seats.

Montgomery County Democrats have a two-to-one voter registration edge over Republicans. However, in the past internal bickering among Democrats, if not out-and-out warfare, has so fractured the party that despite its substantial lead in numbers of registered voters, it has been unable to win the Montgomery County executive's post, or elect a Democrat to Congress.

Republican James P. Gleason is currently county executive, and Republican Newton I. Steers is the area's congressman. By contrast each of the seven members of the Montgomery County Council is a Democrat.

The two Democratic party groups each has a different method of choosing its endorsing delegates, according to officials of each group - some of whom are members of both groups.

The Democratic Coalition is permitting anyone to attend the endorsing convention who is a registered Democrat, lives in the precinct in which he is voting, and has attended at least one meeting in the past. Currently more than 560 people have qualifiedto vote in the endorsing convention according to Stanton J. Gildenhorn, an attorney on the steering committees of both groups.

The Montgomery Democrats group is limiting endorsing delegates to a wide variety of precinct officials, elected officeholders, both past and present, current candidates, and others. Additionally, it has added large groups of party activists who do not hold office. Those elections were held Monday and Tuesday nights of this week. (A list of Monday night's winners appears at the end of this article.)

Party politics in Montgomery County is often taken more seriously than life itself, according to grizzled observers. "They play for keeps out there, and they remember forever," one man said.

In order to lessen the destructive impact of traditional intra-party fighting, officials have this year tried to avoid situations which usually generate conflict and elect Republicans.

One of the steps taken will make it difficult for either of the two Democratic groups to endorse a candidate for county executive. Because of rules each group has passed, a candidate for that office cannot be endorsed unless he receives at least 65 percent of the vote.All other officials can be endorsed with simple majority, or 51 percent of the vote.

By making it almost impossible to endorse anyone for the county executive post, Democrats hope it will be impossible for one side to start attacking another after such an endorsement is made, observers said.

Following is a list of the endorsing delegates chosen by Montgomery Democrats at their meeting Monday night.

District 14: Thomas Abraham; Edith Bardoff; Lynne Corner; Betty Ferrarro; Helene Milman; Samuel Poole, and Helen Templin.

District 15: Irene B. Ansher; Louise Caplan; Dan Cassidy; A. B. Chisholm; J. Barbara Dickey; Gene H. Edwards, Jr.; Norman I. Gelman; John T. Glakas; Wendell M. Holloway; Martin A. Karp; Gilbert B. Lessenco; Diane B. Mesirow; James M. Metcalf; Donald Meyerson; Carolyn Neal; Dorothy B. Osler; Ada R. Pena; Jo Reynolds; Reuben A. Sanders; Frances P. Tolford, and Bernice Jean Wastler.

District 16: Leslie Israel; John Jordon; Shirley Marks; Helen Unsinn; Ted Schneyer; Shirley Frowick; Ellen Gelobter; Judith Heimann; Susan Korn; Jim McKenna; Bill Clune; Eugene Miller; Jane Odle; Betty Lou Hunt; Elsa Skaggs; Madeline Sigel; Paul Stanley; Patricia Horan; Rose Wiener; Thomas L. Siegel, and Gerald Myroie.

District 17: Helen Hocker; Trudy Owens; George Griffin; John Simmons; Elaine Parker; Robert Talbot; Carmen Sayers, Mary McEachern; Marilyn Barksdale; Susan Mash; Jean Grenning; Ellen Einarsen; Robert Buchanan; Barbara Melanson; Catherine Thompson; Susan Gildenhorn; Ruth Loevinger; Maureen Duffy; Jeanne O'Connor; Lowell Jackson, and Kenneth Gamache.

District 18: Mary Helen Boergers; Gary Cahn; Barbara Cantor; Mary Chalker; Joan S. Doherty; Larry N. Gandal; Jon Gerson; Bernice Greene; Timothy (Tim) Hanlon; Leonard Jackson, Sr.; Leonore Kalin; Marlene (Marky) Kirsch; Theodore (Ted) Kleinman; Roger Langsdorf; Janet Levy; Charles Marsteller; Joseph Milstein; Joseph M. O'Connell Marjorie Sonnenfeldt; Molly Ruhl, and James R. Worsley, Jr.

Disctrict 19: Charlotte Abrams; Jim Bortz; Rufus Browning; Ruth Cohen; Sharon Corbett; Alma Gershenson; Gloria Gilbert; Jim Higgins; Art Korf; Barbara Long; Jackie Magazine; Phyllis Matuskey; Barbara Steckel; Hilda Steiner; Nat Sterns; Tom Stone; Lavinia Tarr; Gladys Terman; Chris Wells; Rhonda Williams, and Dick Willems.