The transfer rule for the call handler can only be configured to dial a single phone - by default this is the primary extension of the call handler if one is provided but you can set it to be any number you like. You can't, however, have it ring the phone for whatever alternate number you reached the call handler with - if you want to have the call handler ring different phones based on different input you'll have to create multiple call handlers for that.
If you have a lot of these you can check out the Bulk Handler Builder tool on www.CiscoUnityTools.com...