[Freeswitch-users] Paging and Intercom

How is everyone doing intercom and paging? We are having problems with Grandstream phones where they put an active call on hold to answer the second call if they see the "auto answer" headers. Do all brands behave this way or is this something unique to Grandstream? I was thinking earlyier about handling this from the switch, but since current phones allow you to log in to multiple accounts even across multiple switches, it would be impossible to do this from the switch level...