GENEVA, May 26--The Big Four foreign ministers agreed today to plunge into secret bargaining on Berlin and a summit meeting when they resume their conference here Friday. Then they flew off to Washington for the funeral of John Foster Dulles.

Andrei Gromyko, the Soviet Union's top diplomat, and Britain's Selwyn Lloyd hammered out an East-West agreement for negotiations to begin in secret Friday. The decision to resort to secret diplomacy came after 12 sessions of stalemated debate on big issues.

The secret talks will pivot around more limited objectives--a stopgap agreement in the explosive Berlin crisis and an agreement for a parley at the summit.

Eisenhower to Attend Rites for Dulles

WASHINGTON--The body of John Foster Dulles will be buried this morning with military pomp in Arlington National Cemetery after funeral services in Washington National Cathedral.

President Eisenhower will attend the services for the former Secretary of State, as will the foreign ministers of East and West nations. In an unmatched show of unity, all four ministers attending the Geneva conference were on their way to Washington for the burial.

Among the other dignitaries who arranged to attend the last rites were Dag Hammerskjold, U.N. secretary general, and West Germany's Konrad Adenauer.

Andrei Gromyko left early from Geneva and paused for a five-hour stay in London. He has accepted an invitation to make the return trip with the other Big Four foreign ministers.