blank row or column on collapsed matrix group

I'm using a matrix report that has 3 group colums (category, productgroup, manuf) and 4 group rows (yr, qtr, mo, sales$$). Is there anyway to suppress the blank row/col if the group is hidden/collapsed, some expression that I can use to set the height = 0 if collapsed/not visible? Right now the initial display shows only Yr and Category with other groups hidden but the blank row/col still there.

Yr
blank line
blank line
sales$$
Category blank col blank col data
Category blank col blank col data
Category blank col blank col data
Category blank col blank col data


Thanks for any ideas anyone might have.