In my peer group, you have to consider everyone beside you as your family, like if that person was your brother or at least someone you really love. There are some values we think they're so important to become part of our group, or if you already are a member of it, you have to see them as The Law. Maybe, the main one, would be loyalty which has a lot to do with respect. You MUST help your friend always you can, an even if you can't, you have to attempt it. In terms of fiancees...actually,I think there's no need to clear anything up,it's obvious...if anyone flirts with any friend's girlfriend, this guy would be killed, inmediatly!!!!(metaphorally speaking).
Apart from this, people succeed in my peer group when you have a really good sense of humour, this is essential! You have to be extrovert as well. We don't trust in shyness, although some of my best friends feel embarrased quite easyly. We greatly value being gallant with girls as well, even though sometimes we laugh at them!
I hope this is enough to let you know more about my second family!!