Freeze sales orders

[HDeriauFF]

Hi Folks

I need ideas / suggestions on how to do a global cart freeze when a user (U) initiated modifications on a specific outstanding Sales Order (X).
The goal is too make sure that all inventory quantities are guaranteed for Sales Order (X) and cannot be consumed by any other Sales Order.

During the freeze
- No other other Sales Order can be created by any user
- No other other Sales Order can be edited by any user
- only Sales Order (X) can be edited by user (U)
- user (U) should have access to the entire stock during Sales Order (X) editing

The freeze ends after the Invoice for Sales Order (X) has been processed.

Thank you for your input!