Dynamic SQL, Return Query Execute with Join

Hi all,
I wish to pass a query text (containing joins) and separate parameters to a
plpgsql function that will return a result set (more than one row) using
RETURN QUERY EEXECUTE, but am having trouble defining the result set because
of the join. Am I limited to the result set being restricted to one table
definition and will need to use a view instead? Sorry if my question is too
concise - I can provide sample code if necessary.

Postgres 8.4.2 on Windows.

Mark Watson