If you have Destroy or Disable Droid force power use that. If you have Force Lightnig or Force Shock, use those.
If you don't have any of that, equip each of your party members with a sheild, pause the game during battle and activate them. Thow all the Ion Grenades you have first, before attacking.
Also, double-check that the setting is on EASY, because this really should not be that difficult.