I´ve seen a Cisco documents (http://www.cisco.com/en/US/solutions/collateral/ns340/ns414/ns728/ns784/713499.pdf) describing some interoperation between CUCM and Avaya through Q.SIG over PRI(T1 or E1). The document didn´t mention Call Pickup Group between Avaya and CUCM, but still on the documment this feature is configured.
Does someone know if it is possible to configure Call Pickup Group between CUCM and other vendor platform? And if it is possible to implement these integration through PRI QSIG and/or IP trunks?
That's not possible, the CUCM DB does not share that information with other systems so the feature only works for phones within the same CUCM cluster.
You can configure callback over QSIG, but not call pickup
If this helps, please rate
I've never seen Call Pickup groups work split between two systems - of the same type, or different.
For most migrations this doesn't become an issue, as you would typically migrate a department at once...