Yes, you can. I'm not aware of specific documentation for this, but a couple of notes:
- Make sure you use unique resource accounts (e.g. JT user in particular as that is automatically managed by UCCX and one cluster WILL break the other)
- I would also use unique AXL accounts and probably RM accounts. RM you could share between clusters to just have one RM account to associate any agent phone to, but it's safer to have single-purpose service accounts.
- You can't assign a user to a particular cluster - so you enable IPCC Extension on one user, they appear in 'resources' on both UCCX servers.