and the above is the automatic drill down way to do this
Another way is to use alternatives (but not available for a table. Maybe use a Pivot Table) The enables a drill around feature. I prefer alternatives (when Im doing a chart for myself) as I'm in control. I don't have to follow the preset drill down
For example if I drill by
with alternative I can drill by Products to Customers if I want to. Or view all sub-products or customers
But if I'm setting a chart up for other users I often pre-set the sequence.
Not as you have stated above. Unless it can be done using an extension (although what sort of chart do you want).
One option to do this is just have one dimension (Product Type) and three measures. For example use a combo chart (or a table is another option). With a bar as sum([totalsales]) and maybe use lines as count(distinct total [product]) and count(distinct total [sub product]) (using maybe the secondary axis for the counts).
I would also have a drill down from Product Type to SubProduct. Sort of like this (its one example I have in my demo) but with three measures and drill from Product Type to sub product