Querying forms with relational fields

Hi,

I am stuck with something I think should be so basic to a relational database and can only assume I am missing something.

OK, I have an items form and a many 2 many relationship with a contacts form. When an Item is bought I select the contact who has bought it and this appears on the items form.

Right, I now want to query a list of items bought by people who live in Manchester.

I create a new query. I set the record source to my sold items folder. I add a rule and go to select the field I want to query on - I'm looking for City on the Contacts form. Ok, so Contacts is listed there, but that's it. I can select it and set Contacts = something. But this is nonsense I don't have a value for the contacts form, I want to set a value for a field on the contacts form. This it appears is not possible. What I would expect it to do would now show me a list of the fields on the contacts form so I can select which one I want to query on.

Please help!!

Thanks

Matty