I will leave you a link to the Red Venturers, currently they’re on a campaign in the Dragon Isles with a collection of other Horde guilds (as far as I know), hence you might not have seen them in Orgrimmar.
Perhaps the only detail to note is that PCU guilds refrain from raid markers for the majority of situations and instead use actual NPCs (characters with a tox/disguise/prism appearance actually roleplaying enemies, characters, etc.).