In your replies to Gene's replies one reply is missing:
Are you going to be the active property manager, subject to a call at
2 a.m. when the heat doesn't work? Not that it's critical financially, nor that it answers your question about what exactly you own, and which liabilities you own, but it is something to consider - I spend a lot of time on my house for things that, when I rented, I called the maintenance guys for. A faucet here, a toilet there, a thermostat, a clogged drain, ants, chlorine, walkway to be cleaned, doorbell to be fixed, fridge makes funny noises, light missing in oven, A/C ducting has holes, light switch doesn't work, 2nd floor window needs cleaning, shrub dying, tree needs pruning, cat digs holes under back fence, bear claws maple, branch fell, driveway cracked, the list seems endless - and those are 'unusual items', not the routine stuff like watering, fertilizing, landscaping, painting, carpeting, etc.. There may be a 'shared' property manager amongst other owners.
I believe the question you want answered is the connection other than physical to the rest of the complex. E.g. If a section of roof needs replacement, and it is not over any of the six units you are contemplating, are you legally bound to share the bill for the repairs? If the landscaping and apartment maintenance and tenant quality differs from one section of the building to another, is there an overriding HOA authority to enforce a minimum standard?
One other consideration, since you explained a bit more: who owns the other sections of the building? Did they buy in at the same price (e.g. 550K) range and are they likely to walk away too? I believe there is a provision in some States that a new owner has some right to evict existing tenants within a given period of time, which in some instances can be a benefit to upgrading quality, bypassing an otherwise lengthy process, but as part owner your neighbors are closer to you and more of a factor.