Can I offset STR losses against W-2 income if I Airbnb my basement MIL/ADU

[Rachel Karl]

Hello! 
I am looking to purchase a house with a basement MIL (separate entrance) and will STR the MIL. I plan to self-manage it, should be able to easily demonstrate 100 hours and no one works more than me on it, and keep the stays under 7 days. I don't plan to use the MIL for personal use. However, given that the STR it is technically ‘attached' to my Primary residence, could I still offset loss years against my W-2 income?

I have another property that was an Airbnb for 7 years (now is a LTR) and for 2 out of the 7 years, it met all the criteria for the STR ‘loophole’ to apply and I was able to offset losses against W-2 income. However, that property is also a dedicated rental and thus I am not sure how the IRS rule would work if you have STR a portion of your primary residence.

Thanks all!