So... did you know that if you find a 2-piece ground ability you can "double up" on it?
Suppose you like the Klingon Honor Guard's free heal+buff ability it gets from having a 2-pc. set bonus. Would you like to have 2 of them? Easy! Simply equip the Gun and Armor of Klingon Honor Guard Mark (Say Mk X), and your OTHER Gun and Shield of Klingon Honor Guard Mark XI or XII.
Different Marks of equipment count for different sets... and using your 2 weapon slots with identical weapons of different marks lets you do this. BTW: no, the 2 copies of the abilities do NOT share GCD with each other...