Help with a very strange DNA situation

[Graye]

Perhaps this isn't as strange as it first seems to me but I'm at a loss knowing where to go.  I did a DNA test which threw up various interesting links, confirmed various family tree lines and found some "long lost" and totally unknown distant cousins. 

Unfortunately what it also threw up was close DNA links with three ladies who just don't have anything in common with my tree!  Through a bit of in depth research we've established they all have a link to a particular family.  I have none from what I can see and can only surmise an affair or an informal adoption.  The three people concerned are linked via various of 11 siblings, which makes it even harder for me to see where our link is. We are all around 3.3 generations apart, although we are quite different in age.  The latest person to come up with their info has a link via X chromosomes to me whereas the other two don't. I can't decide what this is telling me. I would love to get to the bottom of this but I'm not sure I know how to use the information I have.  Can anyone come up with suggestions please?

[sugarfizzle]

I can't help as such, but presumably these ladies are predicted 2nd - 3rd cousins or similar.

If these three definitely link together, you are very likely to link with them all through the same family, though not definitely.

First step might be to look to see who else they match with on your list. Are you at Ancestry? Shared matches should show at this level. See what brings any other matches together with you.
Then perhaps check locations. If they are all connected to the same place, have you any ancestors from that area at the right time?

Then look at who gets married in the right time frame, are there any children born shortly after marriage, or even before.

The X chromosome may or may not be a red herring. I am an X match with someone at ftDNA, but not the same person at gedmatch.  We have not been able to find out how we are connected at all.

Regards Margaret

[Graye]

Thanks for those ideas.  All four of us show as linked (3rd/4th cousins) via Ancestry and we also match via Gedmatch. The family which seems to connect us is from a geographical area to which we can all link closely. Unfortunately for me that means most of my family anyway so I can glean nothing from that!  Because there are more confirmed DNA links to other parts of my tree I do have a fair idea that I need to be looking at my father's line though.  Based on their trees and an excel spreadsheet to show the various generations it seems I should share a great grandparent with three of them (we all have more or less the same generation gap of 3.3) and slightly more distant with the much younger fourth member, who is presumably the daughter of a closer link.

As you say, the most confusing part is the X Chromosome match/mismatch. I don't fully understand the possibilities on that and it could be an error too.  The most likely candidate at the moment is my great grandmother who was illegitimate. She appears to have invented a father for her marriage certificate and I can't find any evidence he existed or that her mother used anything but her original maiden name. I'm thinking she could be a 12th half-sibling, although the dates (the father I have in mind would have been very young) and her location (7 miles from the others) makes it improbable. I think I need to encourage one of my paternal cousins to take a test!

Thanks for the input.