Web to App tier load balancing help

I have a 2 tier set up where web servers need to load balance traffic to app servers which also requires persistence. The client had it initially setup source address persistence but to no surprise that has caused imbalance. There are 2 App servers in total that will be receiving traffic from 4 web servers. The application is Remedy ITSM (port 6543) and I need some assistance on what type of persistence can be achieved for this particular traffic?