Realised tt you have pbt too. Since they're super ich magnet and they are now still free from ich, i guess tt yr water parameters shd be still ok.
Since the newbies dare not come out to feed, you may want to consider:
1) taking out the bullies first and house them in yr sump or betta box if you can catch or
2) re-arrange the rockscape to remove the oldies' terrorities and put everyone in the same stage or
3) use mirror method to ease the aggression of the oldies...
Wish you luck, bro. Maybe can post a pic for us to visualise?