HP Procurve switches usually have a setting so that the ports are told which other ports they can communicate with. An easy setup using this is to only allow communication with the uplink, so that no clients on LAN can see each other or communicate directly.
On a 2600 there is
filter source port
On a 2510 it is
Is this feature available on a 2524 or 2512 running firmware F.05.77? Maybe it is under a different name?