Connecting selection to event

hello all,

i am looking for a way to create an event that will be connected to selecting a specific object in Maya; for example selecting the specific object will immediatly select several other seperate objects ( not his children), or pop up a window.
all in all, a script job that runs full time in the background to check if selected objects is quite out of the question.

any clues to where i should start?

thank you in advance.

I dont think mel gives you any other option but to sheck selection has changed... i suggest you use hotkey instead as a slightly different way.

how is this organized you can select its parents (by goung into parent mode) too but everything else id say is api time!