Calculating Averages for several combinations

["Bert Jacobs" <b.jacobs@pandora.be>]

Using Splus 6,2 for Windows.

Hello,

I have a dataframe with 4 categorical variables and 60 continuous variables.
Now I would like to calculate the averages of the 60 continuous variables
for all possible combinations of the 4 categorical variables (with resp.
13,3,58,23 levels).

Is this possible in one equation or do I have to use the aggregate function
16 times for every possible variable combination 

Any ideas?

Thx
Bert