Irules Question

If Src ip =x , Forward to Pool1

if not Forward to Pool2

The question is :

Can i do the below :

Irule Logic : if srx-ip=x forward to Pool1 + use Def Pool under Vs as Pool2 , by that if something didnot match the condition of src-ip =x will Vs go back to use default pool or it will drop the packet ?

( or it is mandatory to use it at the Irule like : if src-ip =x Forward to Pool1 , if not forward to Pool2 , all in the Irule without depending on default Pool at VS ? )