Is it possible to configure an extension to recieve multicast pages as part of multiple page groups? Looking to install in a school, using phones as paging endpoints. But we want to have multiple page groups: all, admin offices, upstairs only, downstairs only, etc. I know this can be done using ring groups, but can it also be configured using multicast? The way I'm looking at it now, the phone can only be set to listen on a single multicast address/port.