PURPOSE: To adopt an individual number plan at every subscriber group and to improve the economics of an exchange network as much as possible concerning the intersubscriber-group connection regulating system in the exchanging network housing the plural subscriber groups to which plural subscribers belong.

CONSTITUTION: This system is provided with a caller group identification (ID) number detecting means 101 to detect a subscriber group identification number (ID) imparted to a subscriber group 200 to which a subscriber 3 transmitting a call belongs. Further, an in-group callee selecting means 102 is provided to select the subscriber 3 to be called by combining the telephone number of the subscriber 3 to be called sent by the call transmitting subscriber 3 with the subscriber group identification number (ID) detected by the caller group identification number (ID) detecting means 101.