I have a Burnham Series 2 Model B gas fired boiler. Need help wiring a 2nd zone relay to it.?

I'm trying to hook up a second zone relay to my boiler and cannot figure out how to connect it inside the boiler. everything else is done and works correctly. The problem I'm having is, I have the 2nd relay wired to the same wires the 1st zone is wired to inside the boiler itself. What is happening is when the 2nd zone thermostat kicks on the boiler, it also kicks on the 1st zone pump. How do i connect this to work independently of each other? Thanks in advance for your help.