GTM DNS Wide-IP-Pool-Irule Question

Hi, First time poster here. We've got an issue where, with a GTM, we had 1 x WideIP with 2 x CNAME pools sitting behind it. There was also an iRule attached to the WideIP which queried the Active Members in those pools as part of its logic, so as to select the correct Pool. All was working fine.

We've since upgraded from 11.5 -> 12 and a few things have happened :- - our 1 x WideIP has been split into three(A, AAAA, CNAME) - the existing irule has been added to the CNAME WideIP - both CNAME pools have been added to the "A" WIP

As we only ever receive "A" record requests, this causes us a problem as our irule functionality is never triggered. We get a CNAME being returned, as the CNAME records are now sitting under the "A" WideIP, but no irule logic takes place.

We've tried adding the irule to the "A" WIP, but as we are adding it to an "A" WIP, when we reference a pool in the irule, it is expecting an "A" Pool...which we don't have. Consequently, it won't let us add it. Creating an "A" Pool, allows us to add the irule, but then only ever returns the IP address in the Pool.....whereas we need the CNAME from the CNAME pools.

Does anyone know of a way to reference a CNAME pool from within an iRule...or indeed any way round this issue.

Thanks.

Alan.