About a year or so ago I learned who my biological father was and that I have four siblings. Both a
The 4 of them had the same mother and father. Their mother and my mother both had the same maiden name. I'm very curious to find out exactly if the two mother's were actually related and how but I don't know where to begin. My thought process is that it is likely their grandfather and my grandfather were related or possibly the grandfathers fathers. At this point my head starts spinning! Any advice is appreciated! Thank you.