A holiday party at the home of a locally prominent Northern Virginia developer left two persons hospitalized yesterday morning after a Fairfax County man attempting to crash the festivities allegedly stabbed two guests.

Kenneth Silvester, 20, of the Falls Church area of the county, was listed in stable condition yesterday after suffering a deep stab wound to his left side, a hospital spokesman said.

Howard Rutter, 23, of Annandale was released after being treated for an apparent knife wound in his chest that required 25 stitches.

Police said a 19-year-old man, also o f the Falls Church area, is a suspect in the stabbings.

Family members said Silvester and Rutter were wounded around midnight at the home of developer John Clayborne, in the 3000 block of Knoll Drive in the Sleepy Hollow area. The two, both graduates of Jeb Stuart High School, had spent the evening with about 50 other recent alumni on holiday breaks from college at a party given by Clayborne's daughter.

Parents of the two wounded men said they could think of no motive for the stabbings other than a longstanding rivalry between Jeb Stuart and Falls Church High School. "There's an element over there [Falls Church High] that's a little on the rough-and-tumble side," said Kenneth Silvester's father, Edward. "I guess it had to happen, but this rivalry has gotten a little out of hand."

Silvester said his son was leaving the party with a girl friend when four or five former Falls Church students stopped in a van and apporached the house. Kenneth Silvester told the visitors that the party required an invitation.

Howard L. Rutter said his son engaged the intruders on the lawn shortly after the argument began. One youth pulled out a knife and lunged at his son, who attempted to back out of the way, Rutter said.

An intense rivalry between the two schools has existed for several years. Recently it has resulted in several instances of interscholastic violence at athletic events.

Relatives said the party was chaperoned by Clayborne and his wife. The Claybornes could not be reached yesterday for comment.