How can I, in Google Forms and using Google Scripts, set up to 3 checkboxes from a group to be selected, but only in a a concatenated row?

how are you? I'm pretty new to programming, and found myself on the spot. I'm trying to set automatic Google Calendars to create ZOOM meetings (still haven´t got to that part, though) and cross reference the meetings to see if they overlap. Each Calendar gets the data from a Spreadsheet associated with a Google Form.

Users can choose a day of the month and then choose from Checkboxes the hours they'll need for holding their meetings. The trick is that I've set them to be able to check up to 3 options (Did this easily with Gforms complement Choice Eliminator 2), but only if those choices are in a row. So, users could choose "08:00 to :09:00" and "09:00 to 10:00", but never "08:00 to :09:00" and "10:00 to 11:00".

Thanks in advance!