LISTSUBSCRIBERS function needed

[Andreas]

I need for a project a "LISTSUBSCRIBERS" function where is see the
hostid of the signed clients of channel name "xyz". I think the data
is there anyway, because the server uses it, so it should not be too
complicated. Is there anyone who could help me doing that or has
anybody done that already?

Then i have some questions about the limitations of Meteor:

Is there any limitation in the channels? what is the longest channel
name accepted?

It would be another option, to give every subscriber his own channel
with his SessionID as channel name... would that work? in that case i
would have to add the same message into the different channels but
could see with the LISTCHANNELS function if a channel is on and
visited... this way i would see after max 60seconds if a client has
signed out.
How would a big number of channels (200+) influence the performance?

And finally, how can i delete a channel, or when is it deleted
automaticly?

Thank you already in advance for your help and ideas...