I've no real experience to speak of, just I 'bonded' Kale and George then introduced the two newbies. I don't think you'll ever get male pigs huddled up together or washing each other, its more of a mutual (sp) living arrangement. Where each pig has his space, but company at the same time.
As long as you never have blood you'll be fine. My males before always use to rumble and grumble at each other, but its only saying 'I'm boss, you remember that and get out of my way'.
Where do your piggies live?