Units not in a zone trigger

[vettim89]

A scenario I am designing involves a hostage rescue. I am trying to figure out a code that will only allow an event if a particular zone is free of OPFOR units.

A SpecOps unit has infiltrated the area where the hostages were being held and neutralized the captors. However, there are other OPFOR units nearby that can interfere with the extraction. Follow on friendly forces are assigned to destroy all OPFOR units in the area before the extraction helo is sent in to pick up the hostages. Basically I want the event to only trigger if the LZ is clear of enemy units. How could I do this?

Second I want an event to end the scenario once the hostages and all friendly units have been exfiltrated, i.e no friendly units left in the AO. Is there a way to trigger this?

Thanks as always for the help

[michaelm75au]

Basically for the first, it should be an event on a time or 'unit remains in area' trigger with a condition of no units in the area (there is an inArea() method for unit/contact), and probably should be inactive until some primary event happens as the SpecOps eliminating the captors.
Once I wake up, I'll add some code if no-one else beats me to it.[:D]

[michaelm75au]

Event condition to check if a area is free of units from a side.
--------------------------------
-- condition assumed to pass. look for cases where not true
local AOclear = true
-- AO area
local area = {'rp-6074','rp-6075','rp-6076','rp-6077'}
-- get units on a side
local side = VP_GetSide({side='china'})
-- side's unit list print(side.units)
-- process the list
for key,value in pairs(side.units)
do
-- get the unit details
local unit = ScenEdit_GetUnit({guid=value.guid})
-- check if unit in the area
if unit:inArea( area ) == true then
-- yes, then condition not true
AOclear = false ; print('AO not clear')
break
end
end
-- return the status
return AOclear