I have never used one but it would seem to be suitable.
The range depends almost entirely on obstacles between the transmitter antenna and the receivers. Put it in screened box and the range may be a few cm, between antennas in free in free space to good receivers, you might get a few Km. You need to do a 'site survey' (experiment to find strengths at different angles and distances from the transmitter) to be sure.
We used the popular inexpensive radio walkie-talkies, when we needed a means for a sick room to summon an attendant who could be in various other rooms of the building (130 feet long). They worked well.
We also tried building-to-building (1,000 feet distance). I constructed a regulated power supply for the units (to avoid using up two or three AA batteries per day). Communication cut in and out due to many objects intervening (walls building, trees).
The 2-way radios have several channels to choose from. Just tune to an unused channel. The sender and receiver need to tune to an identical channel. If one unit loses power then it starts up on the lowest channel when power is restored. It became an inconvenience since we had to make sure both units were on an identical channel.
Typical store-bought 'family walkie-talkies'. Great for hikers, campers, communicating between separate vehicles, etc. Press a button and talk. Release and listen for response.
You can build a radio system but keep in mind that you're married to it. The least little problem will result in a call for you to 'come right over and fix it'. Most people expect to press one button and talk. They won't use it if it requires that you explain it to them.
Commercial units look nice and are portable. They might 'disappear' unless you fasten them inside a housing. As an alternative you might consider a commercial unit that plugs into house voltage and mounts on a wall so it looks non-portable.