Air Carrier ground employee reported a jet blast encounter during pushback due to crossbleed start procedure.

Narrative

Had an engine gate start on [gate] X; after engine was started I lost communication with my new pushout driver. Pilot notified push out driver he was going to cross bleed to get engine two started. Since [gate] X needs people to block roadway traffic due to the plane leaving the gate area; I was assigned to block the road behind the aircraft. I tried to communicate DO NOT CROSS BLEED; I'M BEHIND THE AIRCRAFT (approx. 120 ft.). Pilot thrusted up engine 1 to get engine 2 started; that's when it got bad for me. I thought I was going to get blown over in my tractor. It was bad; rocking really good until the pilot throttled down. No way should an INOP Auxiliary Power Unit aircraft be put on that gate; nor should anyone allow a cross bleed to take place in any gate area. There is no procedure in place if this should happen again.When I heard pilot say he's cross bleeding; I could communicate with my push out driver via headsets. He never heard me. It was like I was out of range for communication; I heard him; and the pilot Auxiliary Power Unit was out; needed to start engine on the gate. I was holding on tight as I was in extreme jet blast as I stopped traffic for our push back. Do not put aircraft on [gate] X when there needs to be a gate start. Have a plan of action if it happens again.