Friends have to come from somewhere, and "integrators" may just be people who are in the process of making friends while "segmentors" are those who already have a network.

If you are single and just arrived in a new place, you probably won't have a lot of friends, and you will naturally form new friendships in the places you are the most often, and work is an obvious one. Like school is for students. So at least for some time, you will be an "integrator".

The opposite is for people who have been in the place for many years before getting hired, they already have a lot of friends, have a lot to do after work and don't have time to integrate a new group, they will be "segmentors".

Also, especially now, friendships tend to outlast jobs, and therefore, "integrators" can turn into "segmentors" as their group of friends no longer work together.