I am using th latest makepkg version from git. I would like to define some groups globally but exclude certain sub packages from those. (e.g. because they are just libs) I use a PKGBUILD similar to the following:

pkgname=(pkg1 pkg2)
pkgver=1
pkgrel=1
groups=(a b)
arch=(any)

build() {
echo built
}

package_pkg1() {
groups=()
}

package_pkg2() {
echo ok
}

I would assume that pkg1 will have no groups while pkg2 inherits the global definition and would be member of group a and b. But pkg2 will only be member of group a.