Many iso on one iso

I have one problem, I search for the solution and after several hours of google and trying many sort of programs I find something that is very close to my need. And that was on this forum. I thought to put my question on that thread but I close tab on browser and forgot link and couldn’t find again.:bow:
So, here is new thread. I have program in several mdf and mds files. It is OS and I need to make it on DVD, so I could boot from that disc. I have magicISo and similar programs, and I could convert mdf to iso (I don’t know what to do with mds) but I don’t know how to create one bootable ISO DVD from 4 mdf files. I suppose that someone created that 4 files from one DVD. I would like to reverse process?
The thread about which I wrote in upper lines describing how to deal with concrete program. Is there general solution?
Thank in advance

Anyone, please?
4 mdf files and 4 mds files into one bootable DVD.
I can convert mfd ti ISO with MagicISO and after that i don’t know hoe to convert 4 ISO files into one which I could burn one DVD and after that to boot from that because that ISO files are operating system and I need it to repair bootloader

Here ya go…