Rotation MassEdit
MassEdit is essentially an advanced version of search and replace.
There are 2 MassEdit options - editing selected galleries (Mass Edit Selected) and editing all galleries in the query (MassEdit Query).
Mass Edit Selected - in this option the search and replace will be performed only with galleries that you marked with checkboxes.
MassEdit Query - a more advanced option, if you need to edit galleries of one sponsor you don't need to mark them all with checkboxes, it's enough to select the required conditions in the filter in List Thumbs (not thumbs, but conditions) and click MassEdit Query - all galleries matching these conditions will be edited.