Partial credit to http://www.mmowned.com/forums/wow-ex...n-one-mob.html
for reminding me this was possible, but they haven't figured out the exact trick.
Steps to reproduce 100% of the time are as follows.
1) have at least 2 hunters (or as many as 6) with different number of point in imp hunters mark.
2) have the hunter with the lowest rank apply the mark
3) have any hunter ranged attack once to start the built in upscaling of the mark
4) have the hunter with the next higher number of talents apply their mark
5) repeat 3 and 4 until all marks are on
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Projected gains based on 6 hunters with 0,1,2,3,4 and 5 points in imp HM
500% more ranged attack power from hunters marks
200% more melee attack power from hunters marks