Limit Options in Multi-Select List with Behavior

[Deleted user]

Hi everyone,

I'm trying to limit the options of a multi select list based on a choice that's been made in a single select list via Behaviors. 

So the single select listA has values of A, AB and the multi-select listB has values Monday, Tuesday, Wednesday

If single select listA= A, I want multi-select listB to show the values Monday, Wednesday

If single select listA= AB, I want multi-select listB to show the values Monday, Tuesday

Any Ideas how to archive this? 

thanks in advance for any help