How? Add-Separately but keep Sync-quantity

In product editor page there is an option to Add-Separately,
I need to add-separately so that my fixed-product-discount (discount given multiplied by quantity of that product) coupons can be applied.
When they’re not added separately my fixed-product-discount coupon won’t accept the bundled product to be the product that satisfies the criteria (because it is a bundled product created automatically by your plugin.)

But when I turn on the add-separately function, the sync-quantity option of your plugin in the product editor page doesn’t work anymore.
Meaning, people can increase as many bought-together products as they please.

I want the bought-together product quantity to be in sync to the main product bought, and the bought-together product to be an add-separately product.

Thank you