C# accessing several proejct folders in same solution issue

Question

In a C# 2010 desktop I have one solution file that have 4 separate project folders. In two of the project folders I need to access two of the same tables using linq to sql. I do not know how to make each project folder be aware of the two tables. Thus I embedded basically the same *.dbml files within each separate project folder.

  I do not think what I did is the best solution. Due to this fact, I have the following questions:
1. Is there some kind of a way that each project folder can have access to the same *.dbml file? If you can you tell me how to accomplish this goal?
2. One of the project folders is a proxy file. Is it a good or bad idea to have a proxy class (project) folder update a *.dbml? Can you tell how how to accomplish my goal?