Intact group assignment problem

[1] Solves a problem of mapping volunteer groups to sites. The question is brought up whether we should minimize the number of links between groups and sites, or something else.

If we assume that the sites accept more than the demanded number of volunteers, we do not have to split any groups at all. This can be modeled by introducing variables that count split groups. The new objective will be the number of split groups. 

Furthermore, we can augment this objective with a small float times the number of workers, to make it as tight as possible. Result:

                  

[1] A variant of the transportation problem  http://yetanothermathprogrammingconsultant.blogspot.com/2019/01/a-variant-of-transportation-problem.html