Unfortunately, no, it does not seem so. At first when Cross Realm Zones were first introduced, you could hop the different server groups and loot the chest but it seems now that people have gone back to business as usual and everyone is after the chest (for the most part) across the different servers.
Your best bet is trying to group with a 90 who is already on a server that he can help you with AGM. Some realm groups only have 1-3 people going after the chest and a single 90 from that server should be able to take care of them.