ansible_inventory.yml

all:
  children:
    P:
      children:
        P1:
          hosts:
            R1:
              ansible_host: 192.168.0.1
        P2:
          hosts:
            R4:
              ansible_host: 192.168.0.4
    PE:
      children:
        PE1:
          hosts:
            R3:
              ansible_host: 192.168.0.3
        PE2:
          hosts:
            R2:
              ansible_host: 192.168.0.2
    RR:
      hosts:
        R3:
              ansible_host: 192.168.0.3