different pools of servers behind same LB VIP

I don't know if you have additional requirements but you could start with a simple iRule using if/else or switch. Switch would probably be more efficient if you have several apps to check for. Apply a client-ssl profile to the virtual for SSL offloading. You can define a default pool on the virtual that will be used if the iRule doesn't select a specific pool.

Some of the existing posts may give you enough information to accomplish this (and more). Feel free to ask if you have more specific issues going on:

iRules 101 - Selecting Pools, Pool Members, and Nodes

iRule based on HTTP path or Host header

iRule based on path and URI