the most common approach to this issue in Qlik is to use a Link table - this table will sit between your Fact tables and allow for the correct filtering of your data. There are quite a few responses on the community relating to Link Tables, so I won't list them all - but checking one of these will help you to resolve your problem.
Here is one to start with: how to create link table in Qlikview?
Hope that helps.
Please mark this as helpful / correct if your question has been answered to your satisfaction