Rallying in Dirtside II

Hello.	I'm new to Dirtside II, and a question came up while reading
the rules.

A Command Unit can attempt to rally a unit.  Since the rallying unit 
pays
for the activation, the Command Unit can rally multiple units.	Is there
any restriction on where the Command Unit needs to be to rally another
unit?  Or can the Command Unit be anywhere on the board, and the player
just says, "Rally this unit.  Now rally that unit." ?

Thanks in advance for clearing this up for me.

--Greg