There are a few options for assigning bandwidth on Cisco routers. I would probably go for custom queueing for what you are trying to do, and allocate the bandwidth based on the source to destination. It is fairly easy to configure, and is very effective. Remember that any queuing only takes place when the router is congested, if the input is lower than the output bandwidth, then all the packets basically go out normally (no need to queue them).
For a full detail on the options, and also how to configure this, and the other queueing methods, go to
Just a note. The one you don’t want to choose is priority queueing, it is OK if you have voice traffic, as you can prioritise this over everything else, but for normal LAN traffic it is too crude as it can stop anything from one source if the other (higher priority queue) is constantly sending data.