Mr. Sprecher, Mr. Bray and other former Sullivanians say that group members -even those who are married to each other -live in apartments with more than a dozen roommates of the same sex, and are encouraged to sleep with a different member of the opposite sex each night. Mr. Sprecher said that he had never lived with his wife, but their marriage had been approved by the Sullivanians because the child was on the way.

At yesterday's hearing, Mr. Sprecher's lawyer, Sanford Katz, said each member of the group had been assessed $1,000 to pay the legal fees for the pending custody cases.

Mr. Katz also said that Ms. Agee had been married to two other Sullivanians in the last six or seven years - largely to be able to claim medical insurance benefits from their jobs, he said - and that she had lost custody of her oldest child in 1976 in a court battle with her non-Sullivanian former husband after she followed the orders of the Sullivanian leadership and sent him to boarding school at the age of 5. The judge's ruling held that she spent ''more time with her therapist than her son.'' Leader: 'Pack of Lies'

Mr. Paganuzzi said Ms. Agee lives in an apartment with her current husband, Mr. Sprecher's 5-year old son and a younger child, but Mr. Sprecher said the arrangement was unusual and made only because of the pending custody suit.

In a telephone interview yesterday, Saul Newton, the 82-year old director of the Sullivan Institute for Research in Psychotherapy, said the descriptions given by Mr. Sprecher and Mr. Bray were ''a pack of lies.'' He called Mr. Sprecher a paranoid schizophrenic and Mr. Bray a liar.

''I don't have the kind of influence they say,'' said Mr. Newton, who disputed Mr. Sprecher's interpretation of his philosophy and said he had close relationships with most of his 10 children. He added that, if people affiliated with the group chose to cut themselves off from their families, it was probably because their families had not treated them well.

''All these people were brought up in the American tradition of self-determination and they do what they want to do,'' said Mr. Newton. ''People who are our members, people who gravitate to work against nuclear war and for a better future for our children, are not so easy to push around.'' Named for Psychiatrist