WEEPING BASEMENT... has me weeping

Well here's the situation, and its got me.
I purchased this home with a basement the previous owner tried to refinish. Unfortunately, though its a decent basement, it has a problem with weeping
By this I mean, it doesn't flood, but water occasionally--- 3-4 times a year, will seep, causing the carpeted floor to get sopping wet, and then the water trickles into the septic drain and out.
Its just enough to make the basement unusable for storage, or anything.

Now. I had this exact same problem at my 'old' home, this weeping, and I solved it. At least there, permanently. Oh, they told me it would never work.... but it did for at least 10 years and is still working. This is what I did.
I first made an incline with dirt running away from the house. Then put plastic sheeting down, then piled rock on top. This made a waterproof barrier. Lucky for me, the ground from the basement to the neighbors driveway was only about 5 feet. So, the water flows to their driveway, then runs down their driveway, and out.

Fast forward to this place. This is what is different, and makes this such a challenge.
Instead of a driveway next door, there's another house with a basement (see pics).
So there's about a 7 foot wide, 30 foot long strip of land between the two houses.
I racked my brain over this. Digging some sort of trench in the middle seems impossible- there isn't enough slope, and that may fail anyway.
My thought was, why not just plastic from house to house, and completely cover this area between the buildings with sheet, and rock on top.

I checked with the neighbor, and they're okay with me doing this if I pay for it. My thinking is, it will keep the water out of both basements. But I just don't know. I can't seem to build an appropriate slope, but the ground does tip up going to the edge of each basement.
The basement windows limit the ability to pile much of a slope.
My house is on the left (white), neighbors is on right.
So. Plastic sheet going from house to house, rock on top, all 30 feet between the two buildings. Water can't get into the ground, so it won't seep into the basement.
The water definitely seeps from this wall side.
Will it work??
Anyone????

 

The water has to go somewhere. What you're proposing makes sense as long as there is slope which will carry the water away from both houses - like toward the front or backyards.

 

Is the water issue just in this area, between the houses? Is water flowing into that area from the front or back? Are there any gutters discharging in this area?

So if nothing above is true then you have to consider once you put the plastic down the water it sheds has to go somewhere, so where will that go?