Fire Egress in finished basement bedrooms (NH)

Apologies in advance, but I searched on this topic and can't find my exact case. I'm buying a multi-family home in a town in NH with no zoning. It was built in 1981. NH goes by national fire code I believe. It's an odd setup with 3 points of entry into the basement, but no windows, and I'm looking to find alternatives to an egress fire escape in the bedrooms.

There are 2 already finished units in the basement. Each with 1 bedroom, 1 on each side. I'm not seeking to do any permitted renovations there.

• 1st unit has a walk out door below grade w/2 windows + a door that leads to a shared bulkhead space.
• 2nd unit has a traditional basement stairwell + a door that leads to a shared bulkhead space.

I think the rooms still have to meet the R310.1 fire code in order to be properly rented. Right now they seem illegal, but the town has no zoning, nor does it seem to care, but the town taxes based off a multi-family and seems to know about these apartments. My homeowner's insurance said they'd cover the property in any event (but not my liability). The bank might allow the financing...

But what I want to know is... since each apartment already has 2 entrances and exits, if I could put a second door on each bedroom, and create an emergency escape route that goes towards 1 of the 2 outside exits? It wouldn't be directly to the outside, but it would be an alternative exit. I'm trying to figure out if this would be enough to provide legal liability coverage?

Thanks