title: looking for a clean way to find relationships from a set of nodes
body: <p>I have got a set of nodes and I would like to write a query to find every relationships which exist between these nodes. </p>
  
  <p>Any recommendation? </p>
  
  <p>My first attemp would be a MATCH a-[rel]-b WHERE... and my WHERE clause would be a OR of all the ids I have in my set of nodes. </p>
  
  <p>Any better idea?</p>