Investors & landlords

I have 7 rentals. Spend more than 750 hours a year to manage them. So I claim real estate professional.  One of the requirement to qualify for OBI is spend more than 250 hours in rental services across all properties. Can I NOT group them as one 'enterprise' as someone mentioned here it will create headache for future reporting if one sold later. Under the question 'Do you want to take QBI safe harbor?' Can I choose the 2nd option - Yes, for 'property X' only , Do I still qualify?