DiVincenzo {\em et al.}({\tt quant-ph/9803033}) and O. Cohen (Phys. Rev. Lett.{\bf 80}, 2493
(1998)). Instead of considering three-party states in which one of the parties, the assistant,
performs a measurement such that the remaining two parties are left with on average as
much entanglement as possible, we consider four-party states where two parties play the
role of assistants. We answer several questions that arise naturally in this scenario, such as …