Your friends will only meet up with you in the city.
They’re outsiders now. They haven’t been introduced to the majesty and magic of the Bronx, so to them it’s a faraway land at the extremities of the MTA’s reach. They probably won’t be willing to take the two/three hour subway ride from Brooklyn or to give away part of their soul to pay the bridge tolls. My advice, get used to taking the 1,4,5,6, B or D, because they’re going to be your only connection to other-borough friends. And you will quickly learn to read the service changes posters, because you will get screwed (I’m looking at you, 6 train).