This is an excellent example of reading from multiple PLC and at the same time read and writing to a a particle PLC.
All these is achieved using one TON (timer) function block but message exchanged being done at different time slots.
PLC A is being read at 8th second mark and PLC B is being read and written at 10th second mark.
Here are the configurations fotr all the 3 MSG function blocks.
You can us the .EN trigger to trigger MSG blocks as well.