there is no functions included in cuelux to do it but the best way, and the way i do it is to create a cuelist with shutter on, and shutter off cues, to make it great create 4 or 6 cues, you make one cuelist like this for each fixtures, and you set the condition to follow and you set the delay for each cue at differents times to create a random frequencie effect.
Once it's done you put all these cuelist into a stack, and this way when you start your stack you will have all your fixtures making random strobe...
i hoppe it will help you!