11 d instead of the second table db 11 b and the service control point scp executes a job called as u201c off net zone u201d assuming now that the subscriber 1 a dials the telephone number u201c dddddddd u201d the communication path 20 is established in the composite communication network 21 and the leased line 3 forms a part of the communication path 20 as follows the exchanger 22 a supplies the telephone number of the subscriber 1 a or the identification number of the caller u201c aaaaaaaa u201d and the telephone number u201c dddddddd u201d of the destination 23 to the service control point scp the service control point scp starts the control sequence shown in fig5 the service control point scp searches the first table db 11 a for the identification number u201c aaaaaaaa u201d of the subscriber 1 a and specifies the identification number u201c ggggg u201d of the virtual private network and the identification number of callers area u201c a u201d as by step sp 11 subsequently the service control point scp checks to see whether or not an identification number of caller 39 s area is found at step sp 11 as by step sp 12 if the answer at step sp 12 is given negative the service control point scp determines the communication through the prior art method and a communication path is established in the public network 22 as by.