How to prioritize an application's network interface use?

We have a OSX.10 MacPro that runs AFP (apple file protocol) file sharing services (client version, NOT server) on a gigabit network with approximately 20 machines.

A regular need is 1 or several networked clients streaming (playing via application) from the MacPro via a file sharing volume. From the client, process is:

• Mount MacPro volume with large video files
• Open audio editing application
• Open video playback window, find video file on mounted volume
• Hit play

This works fine until another client copies files between the MacPro and another device. As soon as this operation begins, the machine streaming/playing the video starts to stutter.

Is it possible to prioritize the streaming application operations over the file copying operations?

The goal is to allow both operations without any stutter to the video playback - essentially prioritizing the MacPro's focus to the video playback.

We already plan to add a smart managed switch between the systems and MacPro, using QoS to prioritize video port streaminga the network level. However, I suspect that the MacPro's operating system (osx) may also need to be told how to prioritize the streaming versus basic file sharing traffic.