While a custom dialing pattern can be implemented to allow international dialing from the OBi100 through the OBi110 SP2 (Localphone), why not consider implementing
Single-Stage Dialing Through Any OBi Trunk in both OBi's? Then you'll have total flexibility to make calls from either OBi out any of the five trunks you have available.
For example...
Normal calling from either OBi out its own trunks doesn't change.
To place calls from the OBi100 though the OBi110 Localphone trunk (SP2), you would simply dial 2 **2 + 011 + country code + number.
To place calls from the OBi110 though the OBi100 Anveo trunk (SP1), you would simply dial 3 **1 + number.
IOW, you simply prefix normal dialing with a single digit that represents the remote OBi.