Please Help with Table

Hello -

I am needing some help...! I am creating a table from a large set of data. 

The table needs 3 categories:

- Category 1 

sub category 1

sub category 2

sub category 3

                               Column Total 1.        Column Total 2.      Column Total 3. .......... 

- Category 2

                               Column Total + Column Total 1.        Column Total +Column Total 2. .......

- Category 3  

There will be 6 columns ^ and EACH category (1,2,3) will need a row of its sections totals. 

Category 2 & 3 will need the previous totals added to its sections totals. 

Category 2 Totals: Section + Category 1

Category 3 Totals: Section + Category 2 (which is the sum of 1&2)

Please help me. Any examples or files are a big help. Thanks.