Possible ways around the 4 unit limit for conventional financing?

[Michael Goldsmith]

Here's a very bizarre scenario that I'd like to bounce off of all of you.  I'm looking at a property that has a house, and 2 duplexes on some acreage.  Three of the 4 units are already rented, and the 4th isn't currently habitable.  I think they started to do a reno and kind of lost interest in it or something.  

Conventional wisdom dictates that the property has 5 units on it (even though only 4 can be occupied), and therefore it wouldn't be able to be financed through a conventional mortgage, and would need to be commercial... which I all kinds of don't want to do. I was planning on buying a place FHA, or some other low down payment type program when I stumbled on this property in my digging.

So... is there a way around this? Can I break up the parcel into two pieces- one with the SFH and acerage, and one with the two duplexes, thereby qualifying for some flavor of conventional/ residential mortgage? I believe it's all zoned residential, and the duplexes are some sort of grandfathered into something since they were originally built in the 60's.

I know I need more info on the property to say with any certainty, but before I spend the time digging, is this even possible?

Thoughts?