Hi @mprichodko I believe a shot at it would be to create an Active list that looks if “Last sequence enrolled” has ever been equal to the number of that particular sequence [it is the number that can be found in the URL when you click to edit the sequence]. I am not 100% sure what happens when they have been enrolled previously in more than one sequence but it is the best way I could find so far.
I hope it helps.
Best wishes,
Pam