I have a folder of PDFs that are a 1:1 relationship with an MXD. Each plan is a floor of a building. In the screenshot below, WHBFD325 is only one floor, so no modifications need to be done to that. In the 4 files for WHBFD364, I would like to merge the 4 PDFs into one PDF with _1 being the first page, _4 being the last page. The merged file name would be WHBFD364. After the merge is complete, I would like the 4 files that end with _1, _2, _3, _4 to be deleted. I am not sure where to start, but any advice or links would really help me out.

I am looking at the PDFDoc ArpPy commands, but nothing looks promising so far.
PDFDocument—Help | ArcGIS for Desktop