Archer and Ozzy are the only siblings we've ever had, but they tend to do
just about *everything* together (they even use side by side litter boxes at
the same time :O)  They're at the stage where they aggravate the H*LL out of
the adult cats because they follow around behind them, step for step, trying
to do everything the "big" cats do.  Sammy loves it and turns it into a game
of chase, but every once in a while she'll raise her paw to them threatening
to give them a clout upside the head (but she's a softie and never does).
Demi ignores them, and Jessie will play along for a while but then get
p*ssed and turn around and hiss at them.

Hugs,

CatNipped