Approval management for DORs

Summary

How can we configure approvals for deletions only?

Content

We would like to institute approvals for DORs but only for modifications/deletions -- namely, we don't mind that people add documents, but we don't want them to be able to delete one without someone on our team signing off on it.  I see that we can restrict deletion, but that appears to turn off the ability to delete altogether.  Is there a condition we can use in the Transaction Console/ Approval Rules that will allow all documents that are added to be autoapproved, but modifications/deletions require approval by an approval group?