If you're only using one city (instead of dynamically finding cities that belong to a side), you can use this as a quick method to determine if one side has more groups nearby than the other.

Ex. using East and West

//-- Define necessary information
_position = getPos player; //-- Town pos
_distance = 500; //-- Distance to check for groups

//-- Get nearby west groups
_westInf = count ([_position, _distance, ["WEST","entity"]] call ALIVE_fnc_getNearProfiles);
_westVeh = count ([_position, _distance, ["WEST","vehicle"]] call ALIVE_fnc_getNearProfiles);
_west = _westInf + _westVeh;

//-- Get nearby east groups
_eastInf = count ([_position, _distance, ["WEST","entity"]] call ALIVE_fnc_getNearProfiles);
_eastVeh = count ([_position, _distance, ["WEST","vehicle"]] call ALIVE_fnc_getNearProfiles);
_east = _eastInf + _eastVeh;

if (_west > _east) then {hint "West is in control of the area"} else {hint "East is in control of the area"};