Thank you for the suggestion.

I believe I neglected an important distinction from other questions posted here...apologies...Continuing the previous example, WH1/DEF receipt should be automatically moved to DEF/Stock, and WH1/GHI should be moved to GHI/Stock. The problem I am having is at the purchase order creation time, I am not able to determine where the shipment is going to be delivered until very close to the delivery date...Hence setting the delivery location as WH1 in the purchase order and then adjusting the receipt to WH1/DEF or WH1/GHI does not seem to trigger the rule anymore...

Thank you again for your time in looking into this.

I understand your issue is with triggering the rules as you aren't aware of the receipt location. Wouldn't you be able to directly modify the destination location on the receipt operation associated with that PO when you learn of the delivery location?

There is a manual input that is required to trigger either at the time of PO or at the time of receipt

Couple of other clarifications
- do you have a multiple WH configuration? with receipts across the WH. Your example has 2 receipt locations but within the same WH.. WH1/DEF and WH1/GHI

- Do you have 1 step or multiple step receipt operations

- Are there any user access limitations to these locations/ receipt operations? If Inventory user has access to all, then they can always modify the destination location prior to validating the receipt

Thank you for bearing with me.

In answer to your questions:
- The idea of having WH1 was as a central (virtual) receiving warehouse which I could use to dispatch the receipt to the correct warehouse once the final receiving location has been identified and goods received.
- By default, we are a 1 step receipt operation.
- I am not aware that I am able to change the warehouse once the purchase order has been validated. The receipt operation only allows me to change the location to any available sub-locations... Users have access to all warehouse hence this option is highly desirable if at all possible...Really appreciate it if you could expand further on how this can be done perhaps any screenshot or links to documentation regarding this.

Thank you again.

Thanks for clarifying.

From your comments it is not clear if you do have multiple WHs and receive in them as well? Am assuming it is true based on your comments that you have WH1 as central & the comment that WH can't be changed in a PO or receipt operation

Based on above I would also recommend the concept of central or virtual WH. You would require to make the locations in the individual WH's to be child location of the central WH. Please do refer the documentation for details
https://www.odoo.com/documentation/15.0/applications/inventory_and_mrp/inventory/routes/concepts/stock_warehouses.html?highlight=virtual

This should enable selection of destination location on receipt operations. Along side you might also want to consider receiving in 2 steps to track. 1st Step central to receiving WH (validate once vendor confirms shipping WH) & 2nd step Receive location to storage location within the WH (Validated on physical receipt of stock)

Limiting user access to WH is also possible, quite a few posts on the forums
https://www.odoo.com/forum/help-1/how-to-restrict-warehouse-access-to-certain-users-188115

Hope this heps!