Mark, where you from?
(I'm not a pro electrician, just a long-time DIYer.)
Here, "rings" are usually referred to as circuits and "sockets" are usually referred to as receptacles.
In any case, outside receptacles are required to be Ground Fault Circuit Interrupted or GFCI to avoid electrocution. In most places, yes they can be on the same circuit as some interior receptacles, as long as the exterior are GFCI.
A pro can explain better than me.
He is in the UK.
Hopefully someone from over there will be around to help.
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC.