Perhaps this is true, but I think that, as the group gets larger, the insiders begin to gather into sub-groups, and then treat members of other sub-groups as outsiders, even though they are all members of the same originial honour group. I guess an example would be the Sunnis and Shiites as sub-groups of the Islamic group. However, you don't have to go that broad of a scale to see pattern. In the Military, the various branches treat each of the other branches as outsiders. Within the Navy, we seperated the crew into "Airdales" and "Blackshoes", defining the difference between aircrewmen and ship's company (The aircrewmen were not a regular component of the ship. They were came on board with the aircraft when deploying, and were dropped off at the end of the deployment. The ship's company were permanent crewmembers, serving aboard in port and at sea.)
Further division of the ship's company existing, seperating those who worked below decks from those above. The engineering gang was seperate from the supply people, etc. The Army and the Air Force have similar sub-groups, usually divided along work-related lines. I should also point out that West-Coast sailors looked upon East-Coast sailors as inferior.
It seems to be the natural order of humanity to divide itself into groups. There is, I'm sure, some sort of honour code within the groups, but the code seems to more of a guideline.