kepad controls 2 alarm systems

hi, i have a problem with 2 alarm systems being controlled with 1 keypad, i was programing my mates alarm yesterday until it started doing its own thing then i realised it was my mate messing with his keypad and it was messing up the programing so i came out of the programing mode and my mates keypad arms and disarms my other mates alarm pretty funny but i dont know if i should try and turn the little adjuster in the keypad to try and change the  frequency or something  the alarm systems are both the same make and model and are both thatcham 1 systems so you would have thought they would have set them up as safe as possible so that there could be no way another keypad could open the car so if anyone could help it would be much apriciated as i dont know where to go from here. thanks in advance 

you have to erase the kepad and program again that way u will erase both and only one will be program again.how own your mind, control your life.

MECP certified. always use a DMM

how did it end up this way in the first place?, the keypads are for two different alarm systems but they operate each other but i dont even want to program these alarms they are a pain in the ass, might just have to keep it as it is how about changing the setting inside the keypad itself do you recon this will do anything.

ok thanks for the help guys i think i will just leave both of the systems alone, the funny thing about this is they live in the next street to each other, lucky it aint next door otherwise this would be a very big problem