I was able to do this by setting up a SAMBA share. I already had a SAMBA server running to share some hard drive space, so I added a section to share the DVD drive. I just accomplished this about 5 minutes ago, and it seems to be working...from my MacBook I can see all the files on my Ubuntu box's DVD drive. NOTE: If you do this, you won't be using Remote Disc -- you'll connect to the drive like you would another networked computer. That is, in Finder you'll look under the "Network" place, not in Remote Disc. I don't know if this will work for what you need or not.
If you're already familiar with SAMBA, this should be pretty easy. You'll need to make the changes to the fstab settings per the instructions in the link posted by mende1. Once you do that, update the smb.conf file to add the DVD as a share. I can post the settings I used if you want.
If you're not at all familiar with SAMBA...you'll need to do a little legwork first. If this is the case, you might just try the steps in the link posted by mende1. I already had SAMBA so I figured I could use that. If you do want to use SAMBA, there's some good info out there in the Ubuntu forums about getting that all set up. I'll try to help if you want to go that route, but it's been awhile since I actually set it up and once it worked I was afraid to mess with it. 🙂 Hopefully since you have "a mixed house" you're already familiar with SAMBA.