We would normally do a masonry corbel.. i.e. and 8" block, then 10", then 12" (all grouted solid) and then bolt a 2x4 nailer to the top of the 12" block. For the second floor continue your 8" block on top of the 12" corbel. You will want to use a top chord bearing trusses and hopefully they will be deep enough to to hide the corbel inside the floor system. Make sure you check the wall for the eccentric load the floor system will put on the wall.