For CB radio, due to the way the radio wave propagate. There is a blind zone. Hence the CB may link up with another CB unit 50 miles away. But cannot link up those CB within a 2 miles radius.

Most FMRS radio are low wattage unit, operating on UHF frequency. The low wattage reduce the operating range of the radio unit. Being UHF device, requires line of sight to connect. So if there is any trees or tall building, it will not be able to link up another unit further down the street.

So look for a walkie talkie unit that has at least 5 watt of power and operates on VHF frequency. Such an unit would be more effective within 2 ~5 miles range.