In order to repost an alarm, you may need to use the rawalarm() function from Carstein. I thought there might be a function for that in the action class, but I checked the whitepaper and did not see one there. (The action class just happens to have functions for several of the actions you can do natively within AO profiles.) The nimbus.post() function would work to repost the message and many of the details, but there are some low-level fields that are set automatically by that function, which are likely to make the alarm look a little different on the receiving end.
When you configure an attach queue, you specify the subject, but you do not specify a subject when configuring a get queue. A get queue is only configured with the name of the attach queue and the address of the other hub. Everything in the attach queue is received by the get queue.
It would be nice if you could create a Lua script that would be used by the NAS replication feature or could explicitly trigger replication on an individual alarm, but I am not aware of any options that would allow that.