[CentOS] how to convert 7 cd iso images into one dvd image?

Hi;

how to convert 7 cd iso images into one dvd image?

I am unable to use bittorrent :-(

Home ISP blocking bittorrent; company now blocks bittorrent.

I want/need an old release (CentOS 5.2) to install as a VirtualBox guest.

I suppose I could install from the cd iso images, but it is a pain to
virtually eject and remount cd iso images during the install :-(

So, is there a technique or an open source tool that will create a dvd
iso given the cd iso images?

Or how does one generate the dvd iso given a list of rpm files?
(Assuming I had a list of all of the needed rpm files).

It would be nice if one had something like "make centos_5.2_dvd_iso" :-)

Thanks,
Ken Wolcott
kennethwolcott at gmail.com