configuring COR

softestplease

There are 3 sites (A,B,C), site A connected to the public phone thru PSTN (PRI link). The case is how to restrict the incoming call from public phone number to reach only certain site using COR....

for example, incoming call from public phone number 7777 can only reach site B (not A and C), public phone number 8888 only can reach site C (not A and

please help

Thanks in advance