Hello new2bpdfamily and welcome!
I'm really sorry to hear about all the difficulties (and difficult relationships) you've experienced in your family over the years. I can't say for sure whether it's "common" or not to have many members of a family with similar disorders, but we've got some info and some tools here that will probably help you find the answer for yourself.
Help with navigation is what we do best here. I would suggest you start by taking a look at the Clinical Overview of BPD here:
https://bpdfamily.com/content/borderline-personality-disorder-clinical-overview - it references some twin studies that show BPD could be genetically linked. Other factors like a common environment might also be at play.
I'm also sure that others will have some stories to tell, so I've linked your post here on the Coping and Healing board.
Good luck and please continue to post.
~DaddyBear77