peer to peer communication between Arduino Micros, serial? half-duplex?

Hello all,

I have a few Arduino Micro units, and need to connect them together (in a mesh network) so that every unit in it is interchangeable, meaning that any unit may be in connection with more than one unit. As the Master/Slave form is out of question at this stage (because any given unit cannot be both Master and Slave at the same time, of course) I decided to go for a simple serial communication.

However the Arduino Micro units (and frankly none of the Arduinos) do not have sufficient serial pins and I was advised to use Soft Serial instead. I was looking into the pin out of the Arduino Micro but cannot quite figure out which pins I can use for the serial comm.; I need 4 to 6 serial communications. If not Micro, what other Arduino (or any other solution) would you suggest?

Each unit needs to have the following information ready at its serial ports:

- its ID
- its MAD
- sensor value (analog or digital)

Any help is much appreciated, as the nature of the problem may not be changed. So I need to solve it as it is.