When I did the system at the retirement home we had a similar thing. Addressable system but we had to incorporate valves and flow / pressure switches into the system. There was a little "interface" kind of device that wired between your loop and the switch, what device was actually called I can't remember off the top of my head, but the device was wired into the loop like any other device, was powered off the loop and all you had to do is wire the contacts of your switch to it, set its address and program it in.
BTW in the building we did, there was one loop per floor and in the case of the ground floor this loop served ALL devices on that floor, pull stations, smokes, heats, and all the sprinkler flow / pressure/ tamper switches were on this loop but were programmed in as different "zones" as required. Tamper and pressure switches were programmed to show "trouble" and were wired in the same method as flow switches. Incidentaly it was a Simplex system but I am sure the edwards is similar.
[This message has been edited by Rewired (edited 11-26-2006).]