Add users to user story map

It would be useful if along the left side of the user story map you could add sections for user types.  We are creating a user story map that has a lot of different steps.  In each of those steps there are different user types that participate or have different experiences.  Right now we are solving this by just making a user map per user type, but it would be more cohesive to be able to look at it all together.  Or even if we could color the cards by different user types.  Just something to differentiate would be really helpful!