Complex sentence: Karl Robertson is the drummer for Australian rock group Thirsty Merc as a founding member from 2002, he has performed on all their releases from "First Work" in September 2003 to the single "The Whole World Reminds Me of You" in December 2008.
Split into simpler sentences: Karl Robertson is the drummer for Australian rock group Thirsty Merc. As a founding member from 2002, he has performed on all their releases from "First Work" in September 2003 to the single "The Whole World Reminds Me of You" in December 2008.