Linebreaks in the edit toolbar?

In our wiki, we have many toolbar buttons on the edit page, so we want to split them into multiple lines at
designated spots. My hacked solution is below -- is there a better way?

To implement this, I hacked function mwInsertEditButton in skins/common/wikibits.js, so an imageFile
value of "<br>" causes a real <br> to be inserted into the toolbar.  I added this code as the first lines of
mwInsertEditButton :

        if (item.imageFile == '<br>') {
                parent.appendChild(document.createElement("br"));
                return true;
        }

Is there a better way to accomplish this task without modifying core code?

Thanks,
DanB