Suppression of multiple provisional responses (When customer PBX is Skype/Lync)

Our customer has Lync as their PBX and what we are seeing is that when they have response groups (multiple endpoints) set as the destination for an inbound session, we get a provisional response back from each endpoint. So if there are 10 devices in the group, we get 10x180s, 183s etc for that session within a fraction of a second, and then the provider (Gamma in this instance) drops the session as they see it as spamming. 

 

Is there an ‘easy’ feature in the SBC that we could enable to only relay the first of these provisional responses through, or would we have to write it into a header manipulation? I’ve had a look to see if there’s anything in the session agent config and I don’t see anything obvious there, or in the admin manual