Script to Assign to a role in a group

Lets say I have a group called ABC . In that group, I have "renter" "merchant" "land owner" as roles.

I want to setup a board that will - 1. get them into the group [that easy] 2. have them select with role they are [1 prim for each role] . I need a script that will assign roles.

I seen this once before ....... the creator was the owner . At that time I wasn't looking.

Any ideas

It cannot be done through a script. A custom client (bot) or some sort could do it.