TQuery - SQL/Datasource problem

Picture this:

3 tables - clearing, accounts, rules

two fields from clearing uniquely identify a row in accounts - from this
row, one field + a third field (item_value) from the original row in
clearing uniquely identify a row in rules

I have a TTable on clearing

I use a TQuery to get the id column from accounts. I use this as a
datasource for another TQuery that will return the row from rules, but I
can't find out how to give this TQuery the item_value field from
clearing.

I could do it easily if a Tquery could have more than one datasource -
but apparently they can't (Delphi 1.0)

Is this clear? - if it is I'm impressed. Can anyone help with how to sort
this out?

Thanks in advance
E-Mail appreciated
Wayne