And this is why you have occasional gatherings. To help establish trust and a better sense of community. Every remote position I've held has had at least a yearly get-together for just this reason.
Also you can have small remote social gatherings. Have a lunch together from time to time (video, online) and chat about non-work things. Have an unlisted #team-offtopic channel. Things like that work in my experience if they're just available and not forced.
You can have different forms of meet-ups as well. My current company has the yearly gathering, plus the employees who live locally have a monthly lunch. None of them are on my team, but it still makes for some nice work-oriented socializing.
