Basically something akin to you the MC being the alpha male (non-incest MC please) and turning an entire family into your personal harem.
You can't have a mc corrupting an entire family without you being related. What you can do tho is just not apply the incest patch that comes with most adult games. My 2 recommendations are : Bad Brother Saga and Sisterly Lust. Imo they are better than Big Brother.
There's a game called Snow daze that's exactly like what you want, you can choose to make it either incest or not when you start.