Honestly, the best solution would be to hand off paging on an FXS port to the Valcom paging unit. I'm not sure if the VIP-201 will support that, but I know for a fact that Valcom has an IP solution that you can plug an FXS into, and then use IP based speakers. I think you can use a VIP-801 to interface with an FXO port, but you need to confirm this with Valcom. They are usually very helpful if you call their Presales line.
Configure Multicast Paging on the Cisco IP Phone 7800 Series or 8800 Series Multiplatform Phone
The Cisco IP Phone 7800 and 8800 Series Multiplatform Phones provide voice communication over an Internet Protocol (IP) network...
Add Call Park on a Cisco 7800 or 8800 Series Multiplatform Phone Key Expansion Module
Call park allows the user of the phone to put an incoming call on hold so that the call can be retrieved on another phone. A call is park...