Continental Club Rules

Hi, just needing a bit of help regarding a revamping I'm doing of the UEFA competitions.

Reverting the Champions League back to being solely for champions (that works fine) however with the Europa League I am encountering a problem where teams who won their league (and should only be playing in the UCL) are entering the Europa League as they won their domestic cup that season too.

Does anyone know how to fix this?

Cheers