[TYPO3] Getting all users in a number of groups (MM possible??)

[ries van Twisk]

Hey Guys,

I need to find all users in one group, or in a number of groups.
Now normally I don't mind to do it 'traditionally TYPO3'
but we talk on quite a number of users (+10.000 needs to perform ok).

of course we do pose restrictions on the number of records to be  
retrieved,
it's just that the table is large...

But I don't like the idea of the comma separated list here for the  
number of users.

Now before I make this all MM aware, did anybody do some
performance measurements on getting  data out of a fair large
enough table using the IN SQL clause where the table size
is close (75-90%) of the number of items in my IN clause?
Preferred tested on +10.000 records.

Ries