Therein lies the problem. The secondary, remote cucm is merely a backup system. All phones work from the primary, until it goes down. There is a possibility of an occasion where the primary cucm is up, but the calls will come into the secondary cucm. The secondary cucm is able to allocate the primary cucm's mtp devices, because it's still available, which will result in one way audio in my overly complex setup. It's not possible to split the config per server, because technically there is only one device to work with (sip trunk).

Ideally, I could set the "Default MRGL" sperately from the perspective of the cucm that was processing that particular call. Like a per server service parameter on the voice media streaming service, specifying the default mrgl, which could be over-ridden on a per device pool, then per device basis if need be. I.E. another step between the cluster wide default, and the per device pool config. Any cisco developers listening?

Thanks for the confirmation of what I suspected already anyway.

Travis