There is one Hrebenchuk family living in the city of Zhitomir, Zhitomirskyi oblast (province). Your grandmother may have come from a village in the Zhitomirskyi area, which sounds to you as, Zhithrokovechi. As for finding Kmit and Hrebenchuk family in Canada, try: http://www.canada411.ca/http://www.canada411.ca/ p.s. Hrebenchuk could also be Grebenchuk. If all fails, try Rebenchuk and Hrebeniuk. Good luck!