Apply Automatic Hold On Every Sales order once its submitted for Processing

Summary:

We have a requirement where we want to apply automatic hold on all the Orders of a specific business unit, After it is submitted for processing and order status is processing

We don't want to go for pause

We explored the extension route, but it is applicable only till order is submitted, so cannot use it

Business wants to avoid the Integration Route

Please let us know the best way to achieve this

Thank you