You could wrap each of these with a class name, or combine them into one class. Then include the class on the node you wish it to be applied to. Example:
class myclass {
command => /some/command/with/full/path
}
}
Then in your site.pp, for the node you want this applied to:
node mynode.mydomain.local {
include myclass
}
I wouldn't really get into a habit of using the exec command, as you will most likely end up doing really horrible hacks to get things to work, and that isn't really how puppet is meant to be applied, but that is the general idea of how you get a class applied to a node.