MIDIOverLAN is a program that allows computers to send MIDI signals to each other over Ethernet (LAN = "Local Area Network"). You install it on each participating computer, then configure virtual MIDI ports on each computer in a control panel to receive and/or send. The ports show up in your sequencer as 16-channel MIDI devices like any other. (Many people on this forum use it - that's how I heard of it.) The version I have gives you 16 virtual ports with 16 channels each. I have four of the ports dedicated to sending info to my Giga PC, and the other eight ports go to my VI-dedicated Mac Pro.
As you know, you can only set the standalone to receive MIDI from driver-created MIDI devices. Each of the MOL ports shows up as a separate device, so what I HAD been doing was setting each standalone to receive from a different MIDIOverLAN port (to get around the problem of not being able to narrow it down to a specific channel). It was in this configuration that I was having the problem I described.
Here's the convoluted part. I use DP as a host for my plug-ins on the slave Mac Pro. DP can also generate Interapplication MIDI devices. Since I was not having the problem with plugins in DP, I decided to create 16 interapp MIDI devices in DP (calling them DP Output 1, DP Output 2, et.). Any of these can be assigned to a VI standalone. I then created 16 sequencer tracks in DP, and assigned them to the 16 newly created outputs. As inputs, I assigned individual CHANNELS from one of my MOL ports. (I.e., the 16 tracks had as inputs "Port 1-1, Port 1-2, etc."). This way I was able to split the MIDI signals from one port into that port's individual channels so that the standalones could receive them separately. For whatever reason, it also fixed my problem.
I realize it's pretty confusing - hope that sort of gave you the idea!
PL