Then you'll have to decide to which fact table wou'll have to link your master data (Region, product, calendar etc.).
Depending on the Facts, it may happen, that you'll lose some information if the two fact table are not always linked properly.
For instance: if you have 2 fact tables: sales and offers, which are linked via one key.
Then you'll want to link the product table to your data modell. If you chose to link the product table to the sales table: It may happen that there is no sales data for one product but offers. The offers will not anymore be related to the product, since the sales data related to that product is missing.
You can easily give it a try with a small sample data set to witness it on your own.