I don't even have to test this, and from my limited experience using Maschine I'm going to give my observation. Maschine uses 16 midi channels per group by default so if you're using two ports that makes 32 midi channels. So if you setup two drum kits, then you're out of luck for instrument midi channels unless you make some changes. I'm not saying the OP has this problem, but it's something other people might want to consider. i suppose if you do all of your songs using only two groups, or very carefully watching and managing your midi channels. I would bet even money you run into some kind of problems running two ports with default settings.