Remote students can collaborate in Zoom or using digital tools such as Canvas groups or Microsoft Teams that provide workspace, communication, and file sharing. Students have many other online applications to collaborate remotely (i.e., Zoom, Google, etc.).
If you have made special arrangements for some of your students who are out for a period of time to connect remotely during class, consider dedicating some of your in-person class time for groups of students to work on projects either face-to-face or in Zoom break-out rooms.