How to handle multiple asynchronous requests ?

I have one dought:-Is it possible one application has too many RunL() for handling the active objects asynchronously.

Suppose 2 applications are there both are the handling asynchronously and both are using resources one by one.
Here my dought is how they know which RunL() go first and how they are mutually handling the events.

Any procedure for the two threads handling using the asynchronous technique.I want to handle the those low level threads one by one with my controle how it is possible.

Give me good answer and give some supported information for the above query.