No, it has nothing to do. The multi part files are *very* common because some PC have problems managing big files such as rared Isos, and are lighter to download too.
If there's a one big RAR inside the multi part, only extract it, then open the big rar and extract the contents.
It had been said many times here: To mount Isos first install Daemon Tools, select mount image, then choose your Iso. Now you have to select the virtual drive in the emulator to play or just access to the files inside