Updating contacts across multiple contact lists

Thanks for your input, Vasil.

Sharing of contacts centrally within the organisation is another issue we're facing, but I'm confident we can solve that one, and I'll take your suggestions when I look into that later.

What we're running into now is that we have multiple Contact Lists that we use as mailing lists to reach out to certain people. For example, we might have a Contact List with acoustic guitar teachers, and another with bass guitar teachers. Some of the guitar teachers might also teach bass guitar, however, so those would appear in both lists. If we update the information of a teacher in the list of bass guitar teachers (or in their main Contacts card), their information would not be updated anywhere else. We'd have to go through all the relevant lists to see if the same person needs to be updated in any of them.

We could take these contact lists out of Outlook and into a third-party solution, but we still use Outlook for e-mail, so that would not be ideal. I seem to be stuck between a rock and a hard place, and I'm frankly surprised this isn't possible with Outlook, because what's the point of having Contact Lists if there's no synchronization and they quickly become outdated?

Tagging or labeling contacts would also be fine as an alternative way to categorize them, but that doesn't seem to be possible either.

Any other ideas would be most welcome!