The link provided is how I did it. You need one for ADS-B and one for MLAT.
I have two RPI2s feeding VRS on a laptop(when it is on). so 4 receiver entries in VRS.
The mlat positions will be transmitted to any other feeder software you are using, and they most likely prefer not to get it. If you have a second receiver set up in VRS, then there is no possibility of the data being erroneously forwarded somewhere it shouldn’t go.
Understood, I was aware of that but was curious whether there was another reason. It remains a simple solution for those that are cognizant of whether the other data consumers can accept MLAT.