IMHO, I think it's better to keep a thread to one topic, because it makes it hard to follow a discussion when there is a mix of questions.
You can basically filter a table's dimension values (except using list boxes to make selections) using two approaches:
a) calculcated dimensions
b) using set expressions in all aggregation functions in your expressions
You can see some more details in a recent post:
Instead of a literal, you can use variables to compare the dimension values against.