Not sure whether or not you would still call it a snowflake but you can add a conjoint to table to have the IDs from the two tables to form a many to many join.
Kimball calls it a bridge table.
I think I should deal with the many-to-many relationship with the same way of relational data base: A-->B<--C, A and B is in a Many-to-many relationship with each other and C is bridge to connect
them to each other, Is it right?