Random number of items in sequence

[OU9561]

Hi everyone! I'm trying to recreate this pattern using railclone. I have the little circles with a multi-subobject material, and using a Sequence and a Material operator I can get very close. The problem is that the pattern isn't purely random, what I would like to do is to be able to tell the sequence operator to put one pink circle, followed by either 1, 2 or 3 white circles, and then repeat.
Anyone can think of someway to do it?
Thanks!

[Rokas]

Hi

Hopefully this is what You are after:

[OU9561]

That's perfect, thanks!