Meaning of the Sanskrit Word: vayasyaih

  vayasyaih—by his friends of the same age    SB 7.5.54
  vayasyaih—with Their playmates    SB 10.8.27
  vayasyaih—with Their friends of the same age    Adi 4.155
  vayasyaih—with other playmates    SB 10.11.41

Can't find any compound Sanskrit words containing vayasyaih.