[Icecast] switch a source, idea?

[unosonic]

hi there,

let's say I have a mountpoint /important with a source a, and a mountpoint /notimportant with source b
now I have to switch source a and b so that the content of source b plays on mountpoint /important
mountpoint /notimportant is, well, not so important

of course I can do it manually, but I wonder if there is a trick to accomplish that 
programmatically or within icecast. ideas welcome!
thx, u