Are you asking how to join the blocks without sashing? I haven't tried this, but this should work:
- quilt the blocks. leaving an inch or so unquilted around the edges
- trim the batting to the finished size of the block
- put two blocks, top sides together. Move batting and backing out of the way, sew blocks together
- flatten out blocks. The batting should butt up at the seam.
- lay one side of backing flat across butted batting. Fold other side under 1/4". Whip stitch in place
- repeat with all of the blocks and rows.
- add quilting over the seams between the blocks. Depending on the design, you could do some of this after joining the individual blocks
Like I say, I haven't tried this, but I think it should work