Dynamic Query Based On "formulas" Stored In Table

Hi,

I have a table that looks something like this:


Company Product Sales
1 A 5
1 B 2
1 C 7
2 A 8
2 B 1
2 C 2


I want a query to produce a table showing Products A though D which is
the sum of Products A and B. Result:


Company Product Sales
1 A 5
1 B 2
1 C 7
1 D 7
2 A 8
2 B 1
2 C 2
2 D 9


I have many rows and many summations and the current union query and
supporting queries are pretty messy and not easily changeable. What
I'd like to do is have a third table which would hold the summed
product names and the formula used to get to it (Product D, A + B) and
have a query that can be dynamically based off of that table. Do I
need to use VBA? Does anyone have a better idea? Any help or even a
good search term would be appreciated!


Thanks!
Nathan