Downloading other media resources while live streaming

I´m experiencing this behavior in a webconference app and although I suspect that what´s happening is normal and there is not much to be done to cope with it I decided to see if someone has any ideas =)

Imagine you have a 400 Kbps link to a server and you are receiving a live stream @ 300 Kbps via RTMP, and suddenly someone shares an image in the webconference app. What happens is that the streaming in the receiving end appears to "stop" while downloading the file via HTTP, and after the file has been downloaded the stream "resumes" from where it was. So then you get a delay of some seconds (depending how long it took your connection to download the file) that is never made up for.

The ideal behavior, for me, would be the exact opposite: the stream gets preference and the file is downloaded with the amount of bw left (the file can take a while to download, but the audio and video are not affected, which is for me the desired situation in a web conference).

Is there a way for red5 to send images to flash clients without requiring http downloads that compete with the live streaming?

Downloading the files from different domains would help?

Thanks very much in advance,

Ignacio