Bought house next to my primary. Can I refi both as a duplex?

[Noah William Jorgensen]

I just recently bought the house right next to me what are the chances of refinancing both my primary and this other adjoining SFR to one loan as a duplex? This would save on the interest rate. And to take it a step further do you think I could then get a HELOC on the whole property (both houses). Has anyone ever done this or is familiar with anyone who has?