What you are describing seems to be complex. For example if you are using nRF24 modules there is no communication or connection between them except for the brief period when a message is being sent. That is why I asked about the size and frequency of messages. Your statement "for initial testing i just want to connect and send only one message." is completely unhelpful for the purpose of seeing a solution to your requirement. If you only need two devices and one message the solution is trivial.
There is no easily defined distance at which a wireless device changes from being within-range to being out-of-range. You might get communication at 100m range some times and at only 50m on another occasion.
If several devices are working on the same channel (frequency) as they must if they are to talk to each other then if more than one of them transmits at the same time all the messages will be garbled - that is avoided by having a master to control things.
You may find it useful to study the TMRh20 Network
libraries - but they are not light reading