Walter Rich Owers from Victoria Australia

Walter Rich OWERS was born in Bu Ni, Victoria - his birth being registered in 1878.
His parents were Walter Rich OWERS & Mary Ann EGAN.
Also Francis (Frank) Edward OWERS was born about 1889 in Australia & his parents were Peter OWERS
& Mary Ann EGAN.
Peter & Walter Rich senior appear to be brothers as their parents were Richard OWERS & Lellia/Letitia Laura DAVIS/S.
Walter Rich jnr & Frank OWERS were both living in Dunsandel, New Zealand in 1919.
Did they have the same mother or were they cousins or what?