My whole solution:
Main catch was to use https://github.com/andrewrapp/xbee-arduino Library and use XBees on API mode.
Use XCTU to configure XBees. I had 4 Xbee Pro 868 devices.
Factory reset all.
ID = some number you like. Must be same on all.
NO = 2.
AP = 2.
AO = 1.
NI = Name you like, I named them like ROUTER3, ROUTER2.
Note somewhere the SH and SL numbers, they are necessary to decide where you are sending stuff.
BD = 115200.
This proved that XBee Pro 868 can be used for any sort of mesh you can imagine. But via api mode.