Christian Voice of Lebanon radio reported that West German hostage Rudolf Cordes will be freed this week. Arrangements are under way to free Cordes, 53, who was kidnaped outside Beirut last Jan. 17, the radio said. West German officials have said Cordes is being held by relatives of Mohammed Ali Hamadi, a Lebanese who was arrested in January in West Germany as a suspect in the 1985 hijacking of a TWA jet. Meanwhile, the wives of four hostages--Americans Robert Polhill, Jesse Turner and Alann Steen and Indian Mithileshwar Singh--called on the abductors to release information about their condition. The Islamic Jihad for the Liberation of Palestine threatened Friday to kill the four in retaliation for Israel's "repressive policy" in the occupied Gaza Strip and West Bank of the Jordan River.