[opensuse-packaging] Building just one subpackage?

Dear list, is it possible to build just one of the subpackages that one obs package has? I need to use iptables directly on openSUSE hosts and tried to build the iptables-service that CentOS has as a package, but this is being built from the iptables package, which has some subpackages. So I would like to build just that one subpackage... Anyone done this? Any hints? Or is it possible to only publish one of the packages, not all of them? (I guess not...) Thanks in advance, Johannes