two alarms

If you have two different aftermarket alarms that both use the car's horn and parking light when going off but one of my aftermarket alarm does not have the starter immobilizer can you use both at the same time if both alarms are going off and using the parking light and horn? will it be safe I should say ? Im using both because Im using the starter immobilizer feature thats not on my other alarm.

Can you install an starter immobilizer without cutting the starter wire ? what happens if I just join and slice into the starter wire or wires to the starter immobilizer will it still work?

well one alarm was already in the car when I got it but it has the feature to arm and disarm and a starter immobilizer. Im installing the second alarm that has more features keyless remote start ect. but it does not have the starter immobilizer like the first alarm has and instead of buying a starter immobilizer and installing it when the car has one can I just use both alarms and if I did use both would there be a problem if both alarms are trying to honk the horn together and flash the lights ???

this is a 92 929 mazda the alarm is the bulldog 62i
and the other one looks like hitech ht series
and the the bulldog did not come with a starter kill I have to buy it I just though I could use the first one for the starter kill feature and use the other for the other features but you said its not good to have them both go off and trying to access the lights and horn at the same time.

I will just use the bulldog and install a starter kill.

the bull dog 62I does have a starter kill. manurl is on there website if yuo dotn have it

I need to buy the starter kill
where can I get one?