Sims buying off sales tables even though sales isn't the open business function

So I'm trying to run 4 small businesses out of one building. Two of them are a tattoo parlor and a jewelry store. The tattoo parlor is owned by one sim, and the jewelry store is owned by another. All of the jewelry store items for sale are on the display cases designated for selling items. The tattoo parlor's only function is tattooing, while the jewelry stores functions are browsing and buying items and doing gemology.

 Since we can only have one business open on the lot at a time I expected the only actions that would kick in would be the actions assigned to that particular business. However, when the Tattoo Parlor is open, even though the only activity is Tattooing they will go into the jewelry store. I expected they would go into the other buildings as I did read up on the lot functions with the small business so that in itself was not an issue. However, they are buying the jewelry even though the jewelry store, which does have the function of selling and purchasing items, is closed. So my sim who owns the jewelry store is not getting the sales because of this.

At first, I tried the disabling sales on the shelves, which works but is very tedious to do every time the tattoo parlor is open. Especially since I have about 10 shelves in the store. I thought I found a good work around for this by locking the other business doors to everyone but the sim who owns it while one business is open. Which did work great at first. But then I started getting ghost customers at the tattoo parlor, and if the customer was a ghost they flew right through the walls and still purchased things. Which made me have to go right back and disable sales on the shelves again. 

I don't know if this is an issue with the sales function or an issue with the shelves themselves, but this is a very irritating flaw. I'm not sure if this would be considered a glitch or bug, but it certainly feels like one to me. So, I'm putting this here so hopefully it gets back to the Sims team and they can maybe fix it or find a workaround they can put in for us. I'm going to put in a no ghosts allowed sign for now and and see if that works. Hopefully this is something that can be re-worked though because I don't think I should have to disable sales to all my shelves every single time one business is open when sales is not supposed to be the function of that specific open business.