What about a mechanic in the game that would phase out the mob killed to the previous guild UNTIL the window has elapsed.
So for example Rampage kills Zlandicar, it would spawn at it's normal interval, but is phased out for all Rampage members. Once the variance on the mob has elapsed (giving ample time for other guilds to attempt an FTE) it would then become available to everyone.
Just an idea...
/flame on
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