Multiple CD ISO's into single DVD ISO?

[Eric Wagar <eric@deadhookers.org>]

I have read in a few places that it is possible to put
multiple RedHat
(http://www.linuxcompatible.org/story14425.html) CD
ISO's into a single DVD ISO.

But, I was not able to find any file like a .discinfo
(referenced in above article about which disk, etc) 
on Debian.

Has anyone been able to do the multi CD's into single
DVD?  If so, how?

Thanks
Eric

PS  I ask because I would like to be able to carry a
single disc instead of multiple.  And, I already have
the CD ISO's.