A distribution of small groups across a virtual world map can be more informal than a many-to-many session, and to some extent this format is a functional replacement for breakout rooms.
Some of the platforms employ a retrogaming aesthetic similar to a 2D overworld, while others work from a blank virtual world or one built up of a collage of photos placed by the user.
One popular software for implementing this functionality in games without built-in proximity chat is Mumble.
[1] In 2021, the children's game platform Roblox introduced a proximity chat feature for verified users over the age of 13.
This feature prompted complaints by privacy advocates, since verification involves submitting a selfie and government issued ID to the company, which has a prior history of data leaks.