I should have looked a bit deeper beofre posting the question, looks like I can acheive what I want by using tags.
Yes, tags ought to allow you to do what you want. You can also tag systems for reasons other than IP range -- basically tag systems returned as the result of many different queries -- then apply task by tag as you found here.
You may want to take a look at the ePO 4.6 beta as well: in 4.6 you will be able to apply policies by tag, not just tasks. Also there will be a task catalog so you can more easily manage tasks just as you do today with policies. This included export/import etc.