[Skunkworks] Pfsense : creating sets of users/ips that you want to limit / allocate bandwidth

Hi All i am running a pfsense firewall , i have one little (from my point of view) issue , i have 2 users taking almost 60% of my bandwidth (both web designers so they kinda like need it but am sure they are abusing ). i have setup squid on transparent mode and everytime i try to use the traffic shaper (they used to work) to limit the whole system to like 1 mb , some how the system finds a way after a while to burst the speeds , so my question is 1. can i limit this 2 guys to a bandwidth set ... wanganane na ka 512 Kbps 2. Whats cutting with my shaper? can i use it to limit instead of blocking? 3. -- GG