If I have say a resource Like a Net/Pop Connection
that can only handle 5 connections at once, and I also
run these connections in a Thread pool.

What is the best way to control access the resource, meaning,
I don't push too many connection events onto the thread pool
at once.

The thread pool itself handles multiple resources so I need
a way to only schedule events on the thread pool, IF there
are available connections for the particular resource.

Hope this make sense.