Ability for someone who is not on my team to allow me to view specific GAPP activities they do.

As a city leader, I would like to give GAPP users who visit my city (and are not a member of my GAPP team) the option of allowing our team to view specific GAPP activities they did which occured within my city. (I do not want to first add them to my team or a subteam team I create; I just want a way for them to designate that they want X team to view X GAPP actitvity which they did.) This would 1) allow us to view the number, location, and types of activities from short term visitors to our city (strategic implications), 2) allow visitors to share their activities with us (which they want to do), 3) allow them (and their team members and parent teams) to still see the activities they did in my city on their own respective teams, and 4) negate the need for me to have to create sub-teams which can quickly get messy.