My sister in law wants me to bring my baby to her husbands family’s house.

Walk in wearing the baby in a front carrier. It will be easier to protect their personal space because it is also your space. Also, it will be obvious that it is not a "pass the baby around" situation, since he's attached to you. You'll take the carrier off at some point, but by then you'll have gotten acquainted and most people won't be as interested or feel any social pressure to hold or greet the baby after greeting time is over.

I second the carrier idea. I’ve never had anyone try to touch my baby in a carrier, but they have when she was in a stroller or car seat. Also once baby is out of the carrier, you can just politely say no, you’re not comfortable with passing him around. If people want to take offence to that, fine. I’ve stopped caring what people think since I’ve become a mum. My children and my feelings are more important to me than other adults. I even tell my grandma not to kiss my newborn or not to kiss or cuddle my toddler if she doesn’t want to. And I love my grandma and she is very sensitive so it’s not easy, but my children will always come first.

The heck. Those people aren’t even related to the baby. Tell her to have her own baby to bring there lol

I second that, and recommend throwing in some niceties about how the baby looks kind of like SIL, and how much you look forward to when she’s a little older and can interact with these people (a “no, but…”). If they can’t handle that, they have no tact in which case “baby is really tired/hungry/etc, we need to be going.”