So I have gone ahead and added a Group Headings feature into the seb_accordion template. And it’s fairly simple to implement.
This mod will allow users to Group Fields in the seb_accordion template. It is important to note that you will need to add the field you're using in the
Accordion Heading section of the List View of your List and Search Type to the Ordering View section. So the same field you're using in Accordion Heading of your List View should be the Same field your Ordering View.
Please note that I only included the files I modified (TemplateDetails.xml, index.php, and en-GB.tpl_seb_accordion.ini). You'll see that all you will need to do is copy the first 2 files into the templates/seb_accordion folder and the language file goes into the language directory.