it is possible but a bit tricky. Basically you have two fact tables with a different way and there are two techniques to handle this in QV:
1) concatenation (like you did)
2) linked table
Check this excellent post by HIC here
you will also find a lot of examples on forum if you search by "link table" - basically the idea it to build another table that would link (hence the name) your two fact tables using shared key. The link table is built using all possible combinations of all keys in your source tables.