Merge every two pdfs in a folder then name it with the second filename

I have folders full of pdfs in which I need to merge every two pdfs. The contents are tabs and book chapters. The tabs are the odd numbered files ex 1,3,5 and the chapters are the even numbered files ex 2, 4, 6. When I run the script pdf 1 would insert into 2. Pdf 3 would insert into 4. Pdf 5 would insert into 6….etc. Is there any way to do something like this?