Hi
QUOTE
where a given owner may own more than one UNIT/WEEK
You should have only one table for owners and another related table for the units they own - and probably another for the weeks.
Can't be any more specific without knowing more about your data model, but it really looks like you need to normalise your db which will, amongst other things eliminate the current problem you're having.
Have a look
here for loads of info...........
HTH
Alan