Jeff, thanks for the reply. The database is currently designed as follows :

There is a table ('participant') that contains information unique to each
participating company (eg city location, contact details).

Organisation size, turnover, sector, plan funding rates, etc. (that are
common to participants) are handled via small look-up tables linking to the
'participant' table.

'Salary_Data' is a table that contains all the pay information for each
participating company. It has a job level (linked to a look up table
specifying one of nine levels) and then manually entered data on average
salary and number of posts in the participating organisation. It is
obviously linked to 'participant'.

All the salary analysis queries select on a particular level and then
calculate one of the following - Min, Q1, Median, Average, Weighted Average,
Q3 and Max salary. Union queries then bring the values (eg Min) for each of
the nine levels together for reporting.

I essentially need a mechanism that sits between the existing tables and all
the queries so I can pass selected information through for reporting.(The
selections would always be from the participant table - but as I mentioned
in my first post, I can't predict in advance what they might be.)

HTH

Rob