Need to be able to switch on and off 12 solenoids...while keeping the existing s

Right, very good. I guess the interface would give an on/off button or two and if I wanted to turn all the lights off regardless of status I'd just hit off. As for the actual physical switches, if I hit on multiple times, the light only turns on once and stays on obviously. The only actual indicator that the light is on, is that the light is on haha. I'll worry about that side of it later I guess. Just interfacing with it would be awesome. Oops I may have forgot to turn a light off... log in and hit an all off button or something... or maybe I'd like to remotely turn on the garage light, maybe we were out later than expected and didn't do it before we left. That's obviously possible too which is nice.