CTS and RTS plz help

Dear SIr

We have an IOT project and we are using XBee Pro 900hp with 10k firmware and API mode, we have a situation here we will use like at this project 100+ XBee multi point to point, right now while testing 20 XBee sending to 1 Main XBee we have a problem with the buffer size not all messages received i tried to use CTS and RTS and i still have the same problem.
Thank you

Sound like you need to use API mode instead of transparent mode.