altq merge

and a CBQ example (adopted from /usr/share/pf/queue2):

altq on $ext_if cbq bandwidth 5Mb queue { std, http, ssh }

queue std bandwidth 10% cbq(default)
queue http bandwidth 60% cbq(borrow red) { staff, hackers }
queue  hackers bandwidth 75% cbq(borrow)
queue  staff bandwidth 15%
queue ssh bandwidth 20% cbq(borrow) { ssh_prio, ssh_bulk }
queue  ssh_prio priority 7
queue  ssh_bulk priority 0

block return out on $ext_if inet all queue std
pass out on $ext_if inet proto tcp from $hackersnet to any
    port www keep state queue hackers
pass out on $ext_if inet proto tcp from $staffnet to any
    port www keep state queue staff
pass out on $ext_if inet proto tcp to any
    port ssh keep state queue(ssh_bulk, ssh_prio)