Link Arduinos over 5 acre laser tag field I am building a laser tag system with an Arduino in each gun.

I want the guns to be linked during game play for many different reasons:


Start/Stop game
Nearby teammates
When a flag is captured
etc.


I don't know how to link the guns to one another during game play because the field may be large (e.g. a park). Wifi has too short of a range, cellular would cost, linking to a phone via bluetooth would drain the phone battery (and require each player have a smart phone to play). 

Can you think of another way to link the guns? Radio transmitters? 

Thanks!
You can use nRF24L01+

The chips offer:


Really high range with power amplifier (1km open field radius (776 acres if I'm right) , but fairly high power consumption 100-150mA @ 3.3V) 
High range with PCB antenna (50-80m open field, low power consumption 14mA peak)
Low cost (0.8£-6£ a piece)
Many easy to use libraries available, possible to create a mesh network
High usable voltage range (direct Li-Po for example without step-up)