Can we update just the bill-to address (and not the ship-to address) of a group of IBs using Mass Up

One of my users needs to update a group of Install Base records, all of which belong to a given account. Her objective is to change them all to the same bill-to location.

When we try the IB mass update feature using the 'Transfer Owner' option, it seems to null out the ship-to address if you leave it blank.  She does not want to modify the ship-to address, as these locations are different from IB to IB.  She only wants to update their bill-to locations.

Is this possible using Mass Update?   Would it be possible using the Web ADI feature?