I have a client on a Partner ACS phone system. The issue that is occuring is, when someone is on one extension and another person picks up another extension, they can hear each other. The building was already wired when Partner ACS was installed. Is it possible that if this building is daisy-chained in any way could make these extensions be able to hear one another? I have already moved extensions on 66 block and problem still occurs. Please help, i've been dealing with this for a week now and need some suggestions on resolving this matter.