There may be cases where you wish to share a single Zoom meeting with students from multiple class codes.
Where the class codes have already been joined in to a Single Myplace class site, Zoom meeting activities that are set up may be available to all, or some, of the enrolled users in the site.
This would be controlled by the Moodle Restrict Access settings on the Zoom meeting activity.
Where the class codes have separate Myplace sites it is a little trickier.
Where a Zoom meeting activity has already been setup in a "primary" class site, you can share the Zoom meeting URL (you may need to go into Zoom itself via https://strath.zoom.us/ to find the details) and add a URL resource to the "supplementary" sites.