How to configure pf for three ISPs?

Please help!
The problem is:

There are two NICs (rl0 and rl1). rl1 is for LAN. rl0 is for Internet. So I need to connect three ISPs in rl0. How to configure pf for this case?

Best regards!

how this 3 ISP connections will be present on interface?

1. with vlan-s
2. with different IP-s

p.s. take care for loops with your uplinks ;)
Thanks for reply!

We need three different IPs on rl0 but if it's too hardly to implement or it's too complex etc we also can add support for VLAN