Yes
Make a queue for pc1 and 2, edit that queue to have a max as described above, set it to have a priority of 3 or so just make it smaller then the next queue you will make.
Make another queue for pc3, edit that queue to have the max described, give it a priority of 5.
Go status > Dhcp server > and statically map the macs of those three computers to an IP
under aliases make an alias for each group
Make rules that tell each alias to go to its corresponding queue, make sure to make both an inbound and an outbound rule for both.
The aliasing is optional, but will make it more dynamic and easier to change in the future.