different payloads for datasource in same resource

Ah, ok. So the main thing you want to track is not necessarily the content of the response, but the actual response time. Cool. Might be more elegant to even use internal website checks instead, but that's a bigger leap.

So, do you have the servers and the VIPs in LM as distinct devices?  Sounds like one payload with multiple destinations.  Is that the case or is it multiple payloads to each of multiple destinations?