how to prevent spiral loops

Hi Experts, I'm working to find a workaround to block SIP spiral loops.
I've this scenario:

caller ---> carrier customer (leg A) ---> MY SBC ---> carrier supplier (leg ---> called

 

Sometimes the supplier sends back the call to the customer through a different SIP Trunk and so a loop starts:

caller ---> carrier customer (leg A) ---> MY SBC ---> carrier supplier (leg
                    ^-----------(other supplier SBC or soft switch)--------'

 

In this case MY SBC is not able to detect the loop because the "other supplier SBC" acts as a B2B UA generating a new call.

The second call has a new Call-ID, a new Via with new branch header, a new CSeq, etc.