Restricting all outgoing traffic (QOS)

I need to limit the bandwidth off *all* outgoing traffic from all internal source IP's (or selected IP's or IP ranges) to a certain cumulative maximum. It is not clear to me how to do this or even it can be done. I can see that I restrict by service/port, but I am not sure how to restrict all outgoing traffic regardless of port.

Any ideas or pointers to a solution? Thanks.

- Henrik