A group of Baltimore businessmen announced yesterday that it is confident it can raise $6 million on its own to buy the Baltimore Orioles, but will probably have to borrow the same amount from the state to succeed in its bid to keep the club there.

W. Wallace Lanahan Jr., chairman of the group, said Maryland Gov. Harry R. Hughes has put "a very high priority" on securing General Assembly approval for a $6 million loan.

"It would definitely be an interestbearing loan. We are not seeking a grant," Lanahan said, adding that the amount of interest had not been discussed.

In a statement supporting the group yesterday, Hughes said, "Any proposal submitted to me will, of course, have to be reasonable and meet all legal requirements of the state and, in all probability, will require General Assembly approval. I intend to discuss the matter immediately with the General Assembly leadership."

A 1975 attempt to persuade the General Assembly to lend Bill Veeck some money to buy the Orioles failed. But that plan involved the sale of $4 million in state bonds, instead of an outright loan. Hughes has indicated a bond issue may not be feasible in this case.

The group is trying to raise $12 million to match an offer reportedly made by former Treasury Secretary William E. Simon to Jerold C. Hoffberger, the Orioles' principal owner.

The Baltimore group's announcement yesterday apparently spells the end of a proposal that it raise $6 million to match a similar amount from Detroit businessmen Max Fisher and Alfred Taubman.

Fisher, who is accompanying Hoffberger on a trip to Israel this week, and Taubman have denied, however, that they have made either a formal or informal offer for the elub.

Lanahan and Bernard Manekin, vice chairman of the group, noted their membership consists entirely of Marylanders and pointed to the economic and social implications of a franchise loss for Baltimore, which is undergoing extensive urban renewal.