GENEVA, May 8--The Soviet Union demanded today that East German representatives be brought into the opening session of the Big Four foreign ministers conference tomorrow as full participants. The Western powers rejected the demand. The dispute created some uncertainty about the actual opening of the conference set for 2:30 p.m. Monday.

British Foreign Secretary Selwyn Lloyd met with Soviet Foreign Minister Andrei A. Gromyko late this afternoon in an effort to resolve the disagreement but the effort failed.

G.O.P. Maps Strategy

WASHINGTON, May 10--Republicans have given up any practical hope of regaining control of the Senate next year and will concentrate their heaviest campaign efforts on a few key states.

Sen. Barry Goldwater of Arizona, chairman of the Republican Senatorial Campaign Committee, said a recent survey of political prospects indicates it will be "very difficult for us to regain control of the Senate in 1960."

Jordan Refuses Military Pacts

AMMAN, Jordan, May 10--The new premier of Jordan said today that this country will steer clear of military pacts with either East or West.

Hazza Majali has been under attack by the United Arab Republic's press and radio ever since King Hussein asked him last Tuesday to form a new government replacing that of Samir Rifai.