Spark window changing itself when inactive

I am trying to figure out if there is a way to stop the spark windows from switching between each other depending on which window has a new message in it. I use spark in my job and generally am in at least 2 group convos and between 1 and 4 IM's at once. I need to be able to follow the conversation in a window but if Spark is not the active window on the screen then it changes to whichever conversation has a new message posted which is bad for me when I am tryign to go through files and follow along on a convo when somone else is talking in the group chat and the window switches over on me.