Hi @Tobias Zackrisson - Another great question / idea. We have "kinda" looked at this. We have, on our longer term roadmap, an enhancement to our external transfers that does a percentage based allocation. This was really to assist the outsourcing market where a company may have multiple outsourcing vendors.
That said we spoke a bit about your question internally today and when we pick up that external transfer portion will give due thought to perhaps some internal transfer support in a similar vein (% to a specific queue or group).
For the near term, there is no out of the box feature that does it. I heard from services that we have a customer that uses a callout to a webservice to randomize a number and then Architect makes a routing decision based upon the returned value. But that is really more of a workaround at this point.
Regards,