ATtiny85 serial communication with multiple inputs - serial-communication

Question

In a project, we try to set up a communication network between three ATtinys, where the first must receive messages from the other two. Those other two tinys are connected to two different pins of the first tiny. The first tiny must then receive two strings from the other tinys, one from each, and send it to an Arduino. For the communication we used SoftwareSerial. We managed to receive and send the input from one tiny, but not from both of them, because we could not find a way to read the input from only one specific pin at a time.
This is the code we used:
#include <SoftwareSerial.h>
const int rx=4;
const int rx2=1;
const int tx=3;
const int tx2=3;
SoftwareSerial mySerial(rx,tx);
SoftwareSerial mySerial2(rx2,tx2);
void setup()
{
pinMode(rx,INPUT);
pinMode(rx2,INPUT);
pinMode(tx,OUTPUT);
mySerial.begin(9600);
mySerial2.begin(9600);
}
void loop()
{
mySerial.listen();
if (mySerial.isListening()) {
mySerial.println("Port One is listening!");
mySerial.println(mySerial.read());
}
else{
mySerial.println("Port One is not listening!");
}
mySerial2.listen();
if (mySerial2.isListening()) {
mySerial2.println("Port Two is listening!");
mySerial2.println(mySerial2.read());
}
else{
mySerial2.println("Port Two is not listening!");
}
delay(500);
}
The code above worked without the part after mySerial2.listen();. Maybe the listen-function of SoftwareSerial does not work on the tinys, but if that is the case, is there another way to listen to a specific input pin?
Or do you have any advice what to do?