What I would do is make the relevant chunk of your front matter look like this:
\esb\cat imagecopy\cat*
\zimagecopyrightsid
\esbe
Then turn to the style sheet editor.
Add a new marker "\cat:imagecopy|esb" , with size and position "h" (h=here / inline / before verse), and width "1.0", no border (unless you want one!). If you want to confine the content to a smaller width, you could say "hc" and "0.75" respectively.
Now you can specify unusual behaviour for \pc inside the imagecopy 'sidebar', by making a special styling for \cat:imagecopy|pc (select the base pc style and click on the Add button), e.g., giving it whatever Space After Factor / Line Spacing is pleasing in everyone's sight.
Hopefully, every author is already in their own \pc, in which case everything should now be fully controllable. You can also go over the top and give the sidebar a border, background colour and/or image, and even an identifying graphic, just like any other sidebar might have.