Passing between PLEG devices

I use a separate PLEG for security and lighting and I would like to know if I can somehow “share” information between them? The scenario in mind immediately is that I want to test whether all lights are off as part of one of my security conditions and rather than define all lights as inputs again to my security PLEG it would be far easier if I could do this test from my lighting PLEG and pass the info to the security PLEG?

Thanks

Never mind found that I can set another PLEG as an input and choose condition satisfied. Very nice!

Very good info… And whats the main reason for starting a new PLEG? How do you know when one PLEG is overloaded and your going to need to split it up?