Carlo, yes. The WiNG software does provide functionality that allows you to limit bandwidth either for an entire WLAN or per user on each WLAN. You can find these options in:
Configuration->Wireless-> WLAN QoS Policy->(QoS Policy)->Rate Limit Tab
You'll see in this tab that it's broken up into top and bottom sections.
The top half (left and right) are for rate limiting options for an entire WLAN. (upstream and downstream)
The bottom half (left and right) are for rate limiting options for each wireless client for upstream and downstream.
Once the WLAN QoS Policy is setup, you then apply the Policy as part of a WLAN's configuration.
Go into a WLAN and in the first section "Basic Configuration" you'll see a dropdown for "QoS Policy" where you can then select the WLAN QoS Policy that you created.