Character action/Turn bar for combat

Hello smart people!

Im trying to make a combat system a lot like Grandia (One of my favorite games):

Where there is an Action bar, and when the characters reach the end of that action bar, they get to act.
I’ve gotten the bar to work with a single character, but im not sure how to approach it for several, all with independent speeds. I thought about creating a little image for each character present in the fight, but not sure how i would go about that, since they then have to be attached to the same slider.

Thanks in advance