I know that there are such groups, but don't know how to point you to them; perhaps a Google search will turn something up. I don't know that a half-size difference will be enough of a difference, but ya never know until you try!
I have a friend with feet that are IIRC 3 sizes apart, which is how I know these groups exist, but since she learned that Nordstrom's will let you buy a pair of shoes of different sizes, she's done with such groups and has never looked back!