I'm not sure if this question is more about the disinfection aspect or the sharing aspect so I'll answer more generally. My two parrots reside in cages with less than 12 inches separating them and they do come in direct contact with one another during their own little fights when they are out. They are both flighted so it's not even possible to prevent contact if I wanted to. Therefore I do not sterilize anything that goes between birds.
For example they both use the same
training perches and trees when they are out in the room. They touch the same training props. They play with the same foot toys that are out. Heck they even steel toys/nuts right from each other's beaks.
So naturally when it comes to rotating cage toys, I have no problem grabbing a toy out of one bird's cage when it got bored of it and just sticking it in the others. This actually gets much much more use out of the toys because after they've been chewed up by another bird, it creates a new angle and interest for the other one. For example I will first give brand new toys straight to Kili cause she can play with them without doing too much damage and enjoy them in whole. Then I give them to Truman and he'll tear apart anything he feels like. Then I can give it back to Kili and the split strands and pieces are easier/interesting for her to play with all over again.
For all these reasons, toy sharing is not only economic but also more fun for the birds.