One Squarespace shop, multiple square pos?

I have recently been asked if I can set up a website with a shop for a group of crafters 

each one wants to list their items for sale, but also wants to be able to take their crafts to fairs and shows, and have some form of pos l, that allows them to sell their items only, and to collect customer data. 
 

I’m thinking that the online shop itself shouldn’t be too bad, if I use stripe to distribute the payments depending on category (being their name). The POS though I’m not sure about. 
 

I know that square and Squarespace are not the same thing, and I can use the Squarespace shop with a square card reader, but that would also mean all of them have full access rights to the shop, website and everything in it, which I don’t want. 
 

Can I set up multiple square accounts? And have them syncing inventory via a third party app? That would mean they each have their own square app on their phone, with a card reader, to make their transactions, 

the inventory syncing wouldn’t be immediate, which could cause conflict if an item is sold online before/after it is in person. But am I overthinking this being a huge problem, when it’s actually a little one. 
 

has anyone tried anything like this? 
 

thanks

Katie

xx