I'm a electronic newbie. All I know come from Google and this forum. Sorry for the incorrect terms.

The assumptions are: I have two or more ir with different transmission frequencies. Each ir is modulated by a NE555. They are arduino-independent circuits. I have one ir receiver on Arduino. There's the probability that two or more ir transmissions are simultaneous.

Is it possible to filter the two or more ir transmissions mixed in one signal?

In my mind I imagine this scenario: IR1: 0101010101... IR2:000100010001..

resulted wave is the sum IR1+IR2

Is possible to read the 0 and 1 of the wave to apply an algorithm to divide the two signals? This is how I would see it as a computer programmer.

Or what would be the fastest and most effective way electronically? Could you suggest me links, circuits, examples?

From what I understand, I think I need a Frequency Division Multiplexing but I have not figured out if I can solve it only with the software or do I need a specific hardware.