You cannot reduce the range of SAMs, but if you have several ones, you may turn some of them off if a radio tower is destroyed, and keep them off while the radio tower keeps destroyed.
To turn an AI SAM off you may:
1 - Set its combat mode to "BLUE"
2 - use mando_missiles\units\mando_attackeronoff.sqf
EDIT: the flares for planes are the same as for choppers, for example:
[myplane, 400, 1, 2, true, 0]"mando_missiles\units\mando_missileecm.sqf"
Execute that server side.
The mando_missileecm.sqf parameters are the following:
- Unit that has the CHAFF or FLARES packs
- Minimum distance beetween incomming missile and the unit to drop flares or chaff
- Type: 0 - Chaff, 1 - Flares
- Number of chaff or flares packs, each usage substracs one to this initial quantity
- radio: true/false, if unit sends radio messages indicating a missile incomming, chaff or flares dropped, missile evaded, etc.
- reactiontime (optional): The unit will wait a random number of seconds between 0 and this value before dropping countermeasures. This parameter is optional, if not provided the reaction delay time will be 0 seconds.