Use pool members as source address?

I'm not setting anything, I'm simply attempting look at the client's ip address and check if its part of a 'list' or a pool. This is a customer's requirements based on antiquated business rules/logic. Their data flow has many load balancing points based on how they validate data and once it is in their network it has to follow a very strict path. Rudimentary visual follows: Internet client -> vip1:1234 -> dataflow1_step1_pool -> vip2:4321 -> dataflow1_step2_pool vip1:2134 -> dataflow2_step1_pool -> vip2:4321 -> dataflow2_step2_pool and so on... So at the second load balancing point everything gets sent to the same vserver and i need a clean way of defining where the traffic should be sent. It should be noted that the client is unable to change their infrastructure and the way they operate. The goal is to make the f5 do the hard work. The point of this is for simplified management/administration. I can easily do this is with a datagroup or globally defined list, however, pool members can change daily and having to change the pool member and then verify the datagroups are properly reflected introduces complexity. I will not be maintaining this, the customers will.