We currently support one order per registry for several reasons.
Since an order can only have one shipping address, combining items from multiple registries, each with different shipping addresses, can cause delivery issues.
Additionally, tax is calculated based on the shipping address. If items in an order are being shipped to different regions or states, it could result in incorrect tax calculations.
Limiting each order to a single registry also ensures that Gift Reggie can accurately sync purchases with the correct registry on the back end.
We’re actively exploring support for allowing a single order to include items from multiple registries in a future update.