Create Clones Randomly

i have 7 game object.i make 7 clones and these clones add in array.i want to how to create clones randomly for eg :one clone at time out of 7 or two clones or three or four not more than four clones out of 7.can anyone tell me how can i do this.

thanks for helping me.

http://unity3d.com/support/documentation/ScriptReference/Object.Instantiate.html