Dear Sir: As a Rabbi of an Orthodox synagogue in New York City, I am extremely concerned by the threat to Sabbath observance and Jewish education which is posed by the new structure of double or triple sessions for high schools. Whereas I am completely in sympathy with the desire for the integration of our school system, I certainly would not want this to take place at the expense of the religious integrity and cultural continuity of those who adhere to the Jewish faith.I strongly urge, as an alternative, that students and teachers be given a choice of selecting the early sessions in the new system, so as to insure that no minority will be disadvantaged at the expense of another.Sincerely yours,RABBI NORMAN LAMMNL: rfThis letter was sent to the following people:Dr. Bernard DonovanActing Superintendent of Schools110 Livingston StreetBrooklyn, New YorkHon. James DonovanPresidentBoard of Education110 Livingston St., B'klyn, N.Y.