I have been banging my head against the wall for a month now. The keyword functionality in SFMC is really under par.
Our plan is to have different keyword for different type of communication. For example one for marketing and one for surveys. First of all, it is not possible to connect a STOP-keyword to a keyword which the contact is opted in to. What this means is that when a contact reply the STOP-keyword, you are unsubscribed from all keywords. This I solved by opting the contact back in to the keywords the contact didn't unsubscribe from.
With this, the next problem surfaced. If the contact is added to multiple keywords and opted out from one of them. SMS sent to the keyword the contact is opted out from, still goes through. So this plan failed all together.
Has anyone had a similar use case and how did you solve it? Would additional long codes solve it? My fear is that if we get more long codes. Opting out of one of them would mean you get opted out from all of them.