Merge / Remove Tag Values

I added a multiple choice tag custom field to the project, for names of R&D Owners for each feature.

I thought our users (PM's) would use it carefully and would enter the names of Scrum Masters correct and only once.

I ended up with having 2-4 different versions for each scrum master.

In order to fix that, i tried editing (as admin) the tag values.

I could rename the different tags, so all John Smith variants would be named John Smith, but I still have multiple choices with same value on each feature.

A feature that allows you to merge some tags would be nice...

Or convert the tags into drop box...