Limit amount of drop down selections on a custom form

Site URL: http://bwydyddbraf.co.uk

I sell meals in any quantities the buyer would like. For example, if a buyer would like to buy 5 meals for the week then they would select 5 meals from a drop down menu. The site then takes them to a custom form where they can select any combination of 6(or sometimes 7 depending on what we offer at the time) meal options to make up the 5 meals they have requested. Is it possible to limit the custom form to only allow 5 meals. At the moment I can not limit the number on the custom form so a buyer may pay for 5 meals but order 8 meals on the custom form.

Thanks in advance

Screen Recording 2022-04-07 at 12.57.49.mov