Excluding a list from a list (Exception)

Hi Guys,
I’ve just started fresh in your community , I’m kind of beginner in coding I’ve got to make a camp reservation app. I’ve a reservations list (listreserve) in the database, I want to exclude or except the (listreserve) list from the input from Air Date/Time picker range so that the result is the available dates for booking, any ideas which elements plug-in etc… is suitable to accomplish this task? Many thanks in advance.

Thanks for you great hint, upon which I’ve created two Data type lists called “Account” for the persons who are now going to reserve date and “Main Account” for the already reserved dates ,The “Account” is to be compared with the main list “Main Account”, But I don’t know ,how could I proceed for implement your suggested solution? See Screen Shoots Below.