How did my Count's son get into other County's succession?

[unmerged(15337)]

I started a new game as the von Lenzburg family in Bern. After about a decade I noticed that my Count's oldest son was 2nd in line to the neighboring County of Aargau, after that Count's infant son. In fact, all subsequent successors are the sons and grandsons of my Count. But I checked out the families and I can't see any blood relation between them. So how did my family get into their succession line?

 

[Jasonkp]

Through marriage. Your count's wife must be the sister of the count of Aargau.

 

[unmerged(15337)]

Not so. No relations, male or female. I checked them all.

 

[Jasonkp]

Umm...?
I just loaded the game and the count of Bern's wife is the sister of the count of Aargau (von Hapsburg), so if I were you, I'd check again.

 

[unmerged(15337)]

I'll check it out later today. Thanks for the tip; I thought I looked for that but apparently not or obviously not correctly. Thanks again.