How about a simple solution:

- The last/8 policy was designed to give each LIR only a single IPv4 resource in order to keep future LIRs in the game.

- Therefore: All resources handed out under the last/8 policy can be hold only once by a single LIR.

- If two LIRs merge and both have a /8 resource, they have to give back one of them.

- A last/8 resource can’t be transferred to a LIR which already holds another last/8 resource.