How to merge multiple back ordered delivery detail lines of same sales order line into a single deli

Hi experts,

Due to many times partial pick release, we have multiple split delivery detail lines of same sales order line, and thus multiple move order lines created for each split delivery detail line. But this brings difficulties for our operation team when transact move orders, especially they have to enter serial numbers against multiple move order lines. So they back order all of the delivery lines and do pick release again, and wish to have a single move order line created and assigned.

But this doesn't work, seems pick release program create one move order line for each delivery detail line, even they all are back ordered. How can we merge them into one detail line so as to have a single move order line assigned when pick release again?