After unsuccessfully looking around for instructions on the internet I
took a look at what other PPAs were doing. I'm not a Ubuntu/Debian
user but I wasn't able to find any PPAs that have multiple versions
(there are packages for multiple ubuntu releases but not multiple
versions of the package for a single release).
If you're able to find out how to do it we'll be happy to change our
PPA to keep multiple builds but it seems like this might not be a
feature that Ubuntu's PPA service supports. :-(
-Toshio