I currently feed pairs that are in pens together (eg GG nanny and her goatling duaghter) from only one (washing up) bowl. It is big enough for both of them to get their heads in a the same time. But when they are are in milk and the last 8 weeks before kidding they are fed separately, so I know who gets how much.
If one was ill and had to be separated, then they obviously get their own bowl.