Not possible, that be a good idea if there were some sort of escrow system in place. I wouldn't send hive or hive power(if possible) to another user expecting them to buy it from me because I'd be scared they would take the hp and ghost or something. Alternatively, I would not send them hive first expecting them to send the hp after, not even if I trusted the person, Has to be some kind of smart contract intermediary in place that we all can trust first, and this just isn't the case yet.