Independent Australian action sci-fi movie Occupation has ramped up filming with the casting of four key roles. Joining the fight for survival are Logie-Award winning actor Aaron Jeffery (Wentworth, McLeod’s Daughters), Kat Risteska (Home and Away, Dance Academy), Ben Chisholm (Red Billabong, The Legend of Ben Hall) and Erin Connor (The Suicide Theory). Now in the third week of a…