Hi. I implemented something similar. Suppose, for example, you have a form in which you registered the list of projects (1). On the other hand, you have a form in which you registered combinations of projects (through a drop-down list related to 1) with usernames that can access them (2).

Finally, if in the process you need the authenticated user to see only a list of the processes in which he can participate, what I did was load that list through beanshell and in the 'where' section of the load query I included that the username registered at 2 equals '#currentUser.username#' (see https://dev.joget.org/community/display/KBv5/Hash+Variable#HashVariable-CurrentUserHashVariable)

I see. So its a user-project mapping table and the control is by username. I was looking at a group based solution but I guess this works as well.

I think it is also possible to do it through the groups, taking into account that the hash variable #currentUser.groups.id# exists. I have not tried it but I guess it is also viable to do it with this variable or doing a kind of "explosion" of records through consulting the information that exists in the dir_group, dir_user_group and dir_user tables