I'm having a hard time understanding exactly what you want to do here... a network diagram and more detail would be extremely helpful. To redirect traffic using pf you need to use the rdr-to directive.
Here's an example where I'm redirecting traffic through my firewall to my webserver on the other side:
# redirect external web traffic to darkstat
pass in log on $ext_if inet proto tcp to ($ext_if) port 8080 \
rdr-to 192.168.0.250 port 80
(I'm using NAT so these rules look a little different than if you were just matching and redirecting ingress traffic... see the manpage for details).
To do basic Layer-3/4 load balancing you might try something like this. If you need a Layer-7 aware approach consider using relayd.