So... if the room availability is determined by numberOfPersons, then you should use that field to discriminate the registers and to show only the ones that accomplish a specific rule on that field...
Then reagrding how to select some values in a database, you should see
How to use select clause[
^].
And how to specify a
condition[
^] for the select clause.
Once you've done that you will get the result you are after.
Then you'll have to store that result into a recordset in order to work with it.
Try it and come back with details.
Good luck!