Not sure what you mean with 'would apply for the entire row', dimensionality() is a function you can use in your expression for column 'Products for Previous Year'. You'll need to use a conditional statement (if() function) to return either your numbers or nothing (like an empty string) based on the dimension level. So you'll essentially just prevent QV from showing the numbers on those (sub-)total lines.
There are lots of samples here in the forum (probably also some in the HELP). If you can post a small sample, I assume someone around will be able to help you right away with the expression needed.