Once you select a value, can it be locked?

I’ve created a booking system that allows users to book themselves into, let’s say, 1 of 3 sessions.
Session1 Tom
Session2 Dick
Session3 -

The problem is that a user can book themselves into a session that has already been taken.
i.e. Harry can book himself into session1, overwriting Tom.
Is there a way of stopping a user from overwriting an already booked session?

The app has 3 ‘Choice’ components, one for each session.
The user selects the required session and then selects their name from the list of users.
The users are not currently required to login.

Thanks
Howard

use a filter to hide clicked sessions

Thanks, but not quite what I was looking for.
I would really like the sessions/bookings to remain visible but locked to Harry.

then you cant use the choice component, for this, I will recommend an inline list, with custom action… when clicked it will set a column with the user name, replace checkmark to check… and condition if checked… show notification that this session is booked and not to set column

Thanks Uzo - I’ll experiment with your suggestion.

something like that, just add a condition, if checked… not to do anything: