Shard together characters with the same xp rate

We see all the time that there are people asking for x1 xp rate, others are fine with higher ones, etc. This comes up every now and then, specially with new realms.
What's currently implemented as a solution, a middle ground, is to let each character choose what xp rate they want to play with. While this gets closer to catering all types of players (casuals, old school, "hardcores", etc), there is still a valid complain to take into account: you'll be interacting with, and going through the leveling journey with, characters of other xp rates than yours. This does impact the experience, for the lower xp rate characters, negatively, as comparing is the base to this urge, characteristic of any game, of besting other people.

So, what if there was a "shard", "layer" or "channel" grouped by active xp rate. You get to enjoy leveling with the same kind of people that you are. All should happen automatically, and upon getting to the max level, you'd get to the "main" layer, where everything would function normally.