Yarden Gonen admits she still finds the absence of her sister Romi "unbearable", three months after the 23-year-old was taken hostage during an attack by Hamas at a music festival in southern Israel.Among the festival-goers killed were Haodya and Tair -- 27 and 23 years old -- nieces of Asaf Pozniak, one of the founders of the Hostages and Missing Families Forum.