Lax, I have no idea how to write an UDP plugin.
Why would you need to do that? Because, you know, MacroQuest is already reading the memory anyway.....
Just make a plugin that allows you to pass information between the two instances. i.e. /pass [instance #] [command] or if you want to get fancy, /pass [character name] [command]
Sadly, I don't know enough about the plugin system to code this, so don't look at me. I don't have a reason to code this plugin, and I'm lazy.
Also not sure why such a thing isn't just a basic command of MQ, but oh well =p
If anyone wants to send me a computer capable of running 2 EQ, maybe I will break down and code this =p