I'm not sure I understand your question, but in the .edmx file, you can add as many database tables, which turn into Entity Framework entities, as you want. Then you can reference them all.
If you are talking about related tables (entities) to a table, the Entity Framework makes those relationships automatically. When you reference an entity set and it has a relationship with other entities, there will be access to those relationships off of that entity.
Does that answer your question?
King Wilder, Apr 15, 2012