In the Schengen area, international airport are divided into two parts: Schengen and non-Schengen. For some airports, those are two different terminals. All flights within the area will depart and arrive into the Schengen part of the airport, where there would be no passport control for passengers. A Schengen flight is like a domestic flight.
Non-Schengen part of an airport have a passport control point at its entrance and exit.

Thus typically, european airlines have two lounges in an airport: one in the Schengen area and one in the non-Schengen area. I guess people on the Wiki points out to which lounge they can guest people.