To be honest this can probably be done with Kisame, Water main, Ao, and Naruto or something, if you have them? Mei isn't necessary, I used her for the immobile and her poison was a nice addition, so the water main would be a good substitute for Mei.
I have those ninjas xD Had to leave a comment like that, ya know how it goes when you get frustrated over exams xD
I hope you figure it out. ^^ You got really close from the picture you showed. I just target Tobirama round 2 and 3 so that he is immobile and dies first, I had 3 people lined up to standard attack Earth main. Fire Main was there to sleep Hashirama, but you could find someone to combo him into acupuncture/immobile.