TWO FACTS JOINing?

Can two facts table be joined a common dimensional table?

FACT1 ->Dim 1

Fact2--> Dim 1

Fact1--->Dim1--->Fact2

Unless you have created specific relationships to support a join (not something you should normally do in a dimensional model) you must assume a M:M relationship between any two fact tables.

To combine two fact tables, the process is a follows:

Summarize each fact along common dimensions (keys or attribute values). Summarization creates a 1:1 relationship between the two summaries.
Join the summarized data by those dimensions.

Yes, it's called drilling across.