Redundant SIP trunks using the same DID

[MKH3CX]

We are wishing to setup a second SIP trunk with our carrier that will deliver calls should our primary trunk fail.
I have tried creating a second SIP trunk but it wont let me add the same DID's as we have on the primary SIP trunk
Am I doing this incorrectly?
thanks
MKH3CX

 

[leejor]

Have you tried using wildcards (to replace leading digits) of varying lengths so that the DID numbers, on each trunk, are not exactly the same?