[Centos] Mod_Throttle for Apache 2?

We have some custom software that is put out on our 6 clustered(balanced) webservers. Every 5 minutes that software checks into our server for a new version, if there is a new version it downloads it (20MB file). This happens about 2-3 times per month. Currently there are over 10000 clients that need to download the update. Up until this past week we were able to handle the load and this is putting a serious strain on our webservers. We were hoping to throttle the amount of traffic that each of the webservers would take and the bandwidth that each client consumes.

Previously I've used Mod_Throttle for Apache 1.3 on other projects, but on our new servers they are running Apache 2. So are there any similar solutions for Apache 2?