Forward proxy with an internal and external proxy irule config

Montysinha I know this is old, but for anyone in the future you would set up an IP datagroup with the IPs and either do an iRule or Traffic policy to select the pool based on IP destination matches in the datagroup.

I have a use case to move the GRE tunnels from our routers to the F5s.  Could you share more details on your setup with the GRE tunnels from your F5?  There is not a lot of info save for the following on DevCentral - https://community.f5.com/t5/technical-articles/configuring-a-generic-routing-encapsulation-gre-tunnel-using-big/ta-p/289030