The win/win situation would be to bring your new friend "grade younger" and the bullied guy you eat lunch with to the group of old friends table.
Just play it natural, most people are too concerned about how there being looked at or the pimple on there cheek to notice the flaws of others.
If you try this and they try to verbally abuse either of you, just be sporadic, it will throw them off guard.
If all fails go with what you think is best.
In my experience one really good friend is better than 10 idiots, depending on the situation of course.
