RS485 - each to each communication protocol

Hello,
I'm looking for RS485 communication protocol where each device can send data to any other (each to each, no master)

Can You advice any library ?

Do you need a library ? Do you actually need RS485 ?

If you define the protocol for the transmission then you will know what to expect and how to parse it on the receiving end. As I understand it RS-485 only specifies electrical characteristics of the transmitter and the receiver. It does not specify a communications protocol, only the physical layer.

I’m using RS485 for communication. I’m looking for protocol to use - similar to ModBus for example - but I can’t use Modbus becasue it works as master slave.

I need to have each to each connection.