Accessing other tables/object from my Repository

Question

I have created myself a typed repository interface IRepository that has methods defined such as Save, Delete, FindById, FindAll etc I then created a concrete class Repository that implements all these methods using:

_context.GetTable(typeof(TEntity).

I can than create my CustomerRepository like so:

public class CustomerRepository : Repository<Customer>, ICustomerRepository

This all works great until it comes to joining tables, what I'm not sure about is how to expose the rest of the "Tables" in my context, should I just have a property on my IRepository that I can user like so

from c in FindAll()
join o in DB.Orders ON c.CustomerID equals o.CustomerID
select c;

Where DB is my context.