Finding a connection between two address is the same problem as finding if there is a path between two nodes in a cyclic directed graph. Unfortunately the runtime complexity is linear (see A* or Dikstra's algorithm), and given that there are about 500 million trx and another 1 billion unique addresses used means finding a path can last from minutes to hours.
So you are unlinkely to see a website offer this service, your best bet is to set this up locally on your machine if your hardware is good enough and run the algorithm yourself.