assuming you have root, you could make a new group and put the prod and dev users in it. Then chown -R the directory that has the backup files in it to the new group (making sure it's group write-able)

Since this is a new group, there should be no other files/dir's on the box that are owned by that group to cause a security issue.

Also any new files or directories created in the directory you changed will be owed by that new group.

also not very perlish.. but hey, it works for me on my box.