title: Join on tables from different DbContext - model first
body: <p>In an app with EF6.0, I have two DbContext's created by model first, <code>Schema1.DbContext1</code> and <code>Schema2.DbContext2</code>.</p>
  
  <p>Now I need to do a join on two entities, <code>EntityA</code> from <code>Schema1.DbContext1</code> and <code>EntityB</code> from <code>Schema2.DbContext2</code>.</p>
  
  <p>How can I do this?</p>