I have an XP8 and an RP6 together in a demo system at our store. By linking are you referring to sharing the RM433 (signal and ground connected between them all) which I assume you mean, or by using the expansion port? XP8 and RP6 I have are part of one system file (actually XP8, 2-RP6, and an RP1). THe XP8 and RP6 each have their own RM433 at this point; for no other reason than I already had it connected to the XP8 when I temporarily rigged it up in the system with the RP6. If I have a chance tomorrow, I'll connect the single antenna to both and let you know if I see any problems.