update query

Hi,
I thnk I am missing something obvious, but I an stuck, and seem to need help
getting some fields in a table updated.
Table 1: R_BSA_M
This has fields for JanHires, JanRevenue, FebHires, FebRevenue etc for 12
months, and a Year Field YearIM.
I have a crosstab query that contains some aggregate data whch I need to get
into this table.
Each record is distinctive for four possible field values that also exist in
the table: category, salesRep, referrertype, bsacategory, and so I need to
update the existing record with the correct record from the crosstab query.
Of course, if I create a query with the table above, and also the crosstab,
and create relationships between the four criteria, then the query is not
updateable, and so I cannot simply update the values in the query.

How might I update a table with the contents of a crosstab where there are
many criteria like this?
Any clues or ideas would be gratefully received.
thanks,
Ian Burton