How to set and limit quantity of all products to X automatically?

Hello, did you ever solve your problem. I have the exact same issue, I sell limited edition collections, and don’t want to have to manually set the quantity by color or size. So if there is 100 pieces of an item, then as people buy the small size in black or the medium in red, then the quantity in total goes from 100 to 98. Right now it seems it’s not possible to do that. If anyone has found a solution that would be great.