[arch-general] Groups and GIDs in PKGBUILDs

Hi guys, Is there a policy with regards to GIDs in packages? Here's my scenario: When creating a PKGBUILD, I want certain files to belong to the http group. However, if http might have a different GID on other systems, I'll need to chgrp the files in the .install file, rather than the PKGBUILD, to ensure correct behaviour. On the other hand, if the http group is considered a standard group belonging to the base system, it may be safe to perform the chgrp in the PKGBUILD, and I can be sure that it will map to the correct group when it's upacked on another system. The Mediawiki PKGBUILD in ABS performs a chown to http in the PKGBUILD. I wonder if there's an official list of "safe" groups somewhere? Cheers, Paul