Color tag primary fields in custom table Merged

When you use a tagged many-to-many custom field referring a custom table, the actual selected entries of the table appear with a dark grey background. For example, if you have created a custom table with all the scrum teams each with their own distinct name, with a relationship custom field you can select from the primary field of this table (containing the team name). This is a very powerful feature. However, in our case I would like to attach colors (like you can on tagged custom fields) to the different teams.