Basic Action Super Heroes!

I'm a bit confused on the Villain Die these guys have. What confuses me is the "...between the three of them they share a Villain Die".
Is the Rogues gallery only intended to be used as a group, if encountered separately over the course of several issues does only one of them get to use that die in only one issue, or if encountered in separately in separate issues, would they each get to use the die?

Yes.

If all 3 show up in one issue, only one of them will get to use 1 villain die (unless they're doing a team-up cation, but that would be an unusual thing for villains to do, as they are notoriously bad at working together).

If only 1 shows up in one issue, that one gets to use 1 villain die.