Centering the Last Row of a RecyclerView GridLayoutManager

I have a RecyclerView that uses a GridLayoutManager, and I want to center the last row. Most of the stuff I have found suggests using a SpanSizeLookup & overriding GetSpanSize. I have done this, and (I think) been able to set the span size, but that forces the following items to be pushed farther as well. For example, if my GridLayoutManager has a span size of 5, my last row has 4 items, and my override returns 2 for those last 4 items, they will end up being split into 2 rows of 2. What I need to do is be able to specify the column index along with the span so that the items overlap (even though it will not visually appear that way, since the overlapping area is just empty space). Is there a way to do this?