Have you read this?

http://www.picbasic.co.uk/forum/showthread.php?t=17282

I was able to have a master PIC talk to multiple slave PICs at 115200. The trick is to have slaves enable usart transmit only when spoken to by the master.

I assigned each slave an ID (used in the data stream). The master would wait for a reply when necessary or keep on working.

A calling-all-slaves ID can be used to have them all do something, but they can't reply.

So no need for any comm IC, just straight PIC to PIC connections.

Robert