Effective MIDI setup

Hi
I have been using a microKorg connected to the in/out of my MPC500 in order to record MIDI information to the MPC then use it to trigger the sounds back on a MIDI track, which has been working well.
I now want to add further sound modules to the setup and have looked into ways of expanding the number of MIDI in/outs on the MPC. I have found a couple of different things that might be useful, particularly MIDI merger and MIDI thru devices which would effectively turn the in/out into 4 ins and 4 outs.
What I want to know is, if I had 4 MIDI tracks set up in the MPC, with each MIDI track on the MPC set to a different MIDI channel, and each corresponding sound module set to match appropriately could I use the merger and thru devices to send and receive 4 separate signals to/from the MPC? This might be a silly question so I am bracing myself for the answers I just don't know, as all the MIDI information would still be going in and out through the MPCs one in and one out port.
Thanks in advance for your help!

the outs can all be connected to the same chain as long as the modules are all on different chans, As for the ins, yes youll need a midi merger to do that.