How to selectively disable v-cards inside v-data-iterator

[basebandit]

I want to disable cards marked as assigned when one or more unassigned cards is/are selected and vice versa. This is my attempt to achieve the same

codesandbox

However I am having the following problem. When I select more than one unassigned cards and then unselect any one of them the assigned cards become enabled while there are still unassigned cards selected.
This is what I want to achieve, If I select one or more unassigned cards all assigned cards should be disabled and should remain that way as long as there is one ore more unassigned cards selected and vice versa should happen for when one or more assigned cards is/are selected.