create pool that forwards entire subnet

need to reproduce a forwarding pool in 4.x for a new F5 box running 9.x. my guess is this involves an IP forwarding virtual server

 

 

i'm told the 4.x pool on the old F5 is designed to forward anything destined for subnets, say 172.15.1.0, to other subnets, say 172.15.2.0 or 172.15.3.0. the name of the virtual server is 172.15.1.0:any and the resource is a pool named fwd_pool, it uses round robin mode and has no members, only a keyword 'forwarding' in the member column

 

 

this behavior needs to be duplicated in the 9.x box

 

 

I created a pool called fwd_pool in 9.x but due to the differences with 4.x it is less than obvious if it worked or if the definition is complete enough. also i was expecting to be able to use this pool as a resource for the 3 IP forwarding virtual servers i created but under 'resources' for VS's only iRules is an option, there is no list of pools to choose from

 

 

one other thing, i don't understand how this 4.x pool actually receives or sends any traffic anywhere, there is no destination defined within the pool and other than the name fwd_pool there is no apparent way it intercepts or receives data which it is supposed to forward and with no members in the pool, well you can see this escapes me

 

 

the person who defined this setup is gone. i go to training next month but am tasked with making this work before going.