Are you using Microsoft Access 2007? There's a data type that you can use.
Now the caution ... the multivalue field has received some less than
favorable comments here in the newsgroups because it removes your ability to
modify/manipulate the underlying "relation/junction" table that has to exist
to handle the many-to-many relationship.
If you understand many-to-many, you may be better off, for now, creating an
explicit table and using it (i.e., doing Access the "old fashioned" way).
--
Regards
Jeff Boyce
www.InformationFutures.net
Microsoft Office/Access MVP
Microsoft IT Academy Program Mentor
http://microsoftitacademy.com/