Making parallel connection in junction box?

I have a circuit that I think connects to a junction box and then splits off into 3 rooms to run baseboards. I want to have a look at the junctions. If I was making a parallel connection, would I just connect up all - red wires to red wires and - black to black wires? Attachment 38330 (http://www.doityourself.com/forum/attachments/electrical-ac-dc/38330-making-parallel-connection-junction-box-diagram1.jpg)