If the speakers all have multicast, then that may be a better way to go.
Each speaker area has a "ALL CALL" Multicast IP.
Then each speaker has an "AREA" Multicast IP - SouthEast, SouthWest, etc.
And even further, some speakers might have "GROUP" Multicast IP. (multiple speakers on the same floor - all of 2nd floor)
Although the speakers can be endpoints - I do not have them setup that way, so they do not show as an extension.
Then I set up the Ring Groups in 3cx.
700 - PAGE ALL
701 - PAGE WAREHOUSE
702 - PAGE UPSTAIRS
703 - PAGE DOWNSTAIRS
704 - SALES AREA
705 - MARKETING
etc.