All I can find is threads of high level herbalists discussing if it’s still possible in theory.
Haven’t seen anyone who tried and reported that it doesn’t work at all for rare farming.
I’m pretty sure someone tested it to farm on f2p chars.
I'm not even certain I totally understand what you're proposing... but the only time that you're not anchored to your "Home Realm" is when you're phased into the Realm of your group-leader.
Even in the (unlikely) event that an activity with automated-grouping gave you a leader from a "non-linked" realm, such activities are all "Realm Agnostic" instanced-content and your group-leader wouldn't technically be on a "different" realm from-which to anchor you.
If you want to work the "theoretically possible" angle... I suppose one could:
Queue for (and enter) a dungeon while near a desirable spawn-point,
...discover that your randomly-assigned party-leader happens to be from a distant Realm,
...ask them to "Teleport out of Dungeon" (without breaking the group) and you do the same,
...at which point you would be back "in the world", in a group whose leader is at-that-moment back on their distant home-Realm, and (as far as I know) will have met the criteria to "hop".
A fun intellectual exercise... but even if we assume that Blizzard™ hasn't already taken measures to prevent it from working, it still doesn't sound very "practical".