pf load balancing

[Lucas]

hi list,

i'm working with 3 gateways and want to load balance between them.
after a failure with layer 2 (carp arpbalance) balancing, i tried to do 
it with pf.

the most logical way to do it is with a machine before the gateways 
distributing the load.
there's a way to do it without adding a new machine (and a new point of 
failure) to the set?

thanks in advance,
Lucas