Yes, a group visa is provided to a group of tourists who travel to Belarus together. Technically, it looks like a typical visa stamp, the only difference being that it is stuck onto an A4 format page with the passport details of the group members, and not in somebody’s passport as is the case with an individual visa.
A travel to Belarus on a group visa is a cost-efficient measure, but it is a must that you enter and exit the country together. If someone from the group visa list is missing (e.g. fell ill, changed their mind, etc.) before entering Belarus, it is ok, but everybody must be present when leaving the country.
Naturally, all the passports and respective papers of the group members must be submitted in one package. Members of a group traveling to Belarus on a group visa must enter the country together (e.g. one out of ten cannot come by air while the rest ones are coming in via Polish border).