The seperate frame solution is viable. However, there is another option that is similar in it's simplicity.
Say for example you have 10 MC's, named MC1, MC2... MC10.
You can access them by using brackets.
if you were to do this:
targetme = _root["MC" + (random(10) + 1)];
the variable targetme would then, basically, become a random one of those movieclips to which you can duplicate, delete, move, make invisible, whatever. In doing so it affects the origional movie clip.
Lets say the random(10) came out 5 (add 1 because random(10) is 0-9) and we typed
targetme._visible = false;
MC6 would then become invisible, or could be duplicated, or whatever you needed to do.