Ours do! Four lurcher dogs, all get on very well, don't gang up or go off together; still have their Mum who still keeps them in their place but usually plays tag with them half a dozen times a day! They are all the most loving dogs you could find too but each with their own special character.
Here they are (some of them!)
We've got 2 at the mo, they get on fab. They don't seem to follow eachother too much for now! We said we'd never keep 2 again but that's more because its hard work.
Jimmy and Mouse aren't littermates but share the same mum (Millie) she keeps them in place, I wonder if they realise.
Don't think there is a definitive answer to this. I have had litter mates that have been lifelong pals, also know of them where there have been problems with fighting. It is definitely harder to train them . I think the secret of them getting on is letting them sort out their pack hierachy without interfering. Having their Mum with them probably helps with that a lot.
Yes I agree about Mother /daughter. I have a mother and daughter that don't get on at all. They were fine till the daughter got to about 2 and the hormones kicked in and that was it. Should probably have left them to sort it out but its not that easy with 2 adult Shepherds, and luckily have space to keep them apart. The dam is now nearly 13 and still tries to pick a fight with her daughter given half a chance. I was thinking of same sex litter mates having possible problems rather than brother/sister.
We've got Lucy & my nan & grandad have got her brother. They live about 2 minutes away from us and the dogs see each other most days. Love each other! Always play and i think they always will.