How can i mark an item as pickup only so it can not be purchased with a shipping option?

squarespace 7.1

I have many items on my site but some are too big to ship and must be pickup only. i'd like to make these items so that being shipped is not possible (IE  you can only use the pickup option when purchasing).  

I have a shipping option and a pickup option set up, i just need to be able to hide the shipping option on certain items 

Thanks!