As was mentioned in the first post, whether or not this is a relevant issue depends on your strat for killing Jevlan.
Initially we used the 3cell/balancing method that a lot of people seem to favour for this event, and as a general rule we prohibited the use of AE songs.
There does seem to be some disagreement as to whether AE songs will reach or not, and I can only talk from my own personal experience. Once or twice we experimented with the use of AE songs on Jevlan. I witnessed, firsthand, hate transference from the South cell to people in the Northwest cell. Now, it may have been down to Bard positioning that day, or player positions in the South cell, but either way we noticed a spread of AEs not native to the cell in question (yes the mobs were balanced), and the only reasonable explanation was transference after beneficial buffs or heals hit the Bard.
Anyway, from that point on we restricted ourselves to group songs on this event, until a few months ago when we changed tactics to a variance on those described by eclapton. Now, the playing of AE songs is a moot point as hp imbalance kicks in early on and everyone gets hit by the AEs anyway.