Depends on how handy you are! One of the hassles with smaller tile is the thinset filling the gaps between tile when you press them in to set them. To get these even with the thicker tile will require a thicker layer of thinset. With thicker thinset, getting the tile on an even plane is also tougher since they can tilt or sag in the process. If you get the tile below and above in place, you can use a block to press the small tile in so they are flush and flat. You could use something like a grout float to press them in place as it would be big enough to span onto both of the larger tile.
How much difference is there in the thickness of the tile? If it was say 1/8" or so, you could use a 1/8" notched trowel trowel on that strip, let it set overnight, then apply more thinset to set the tile. You'd want to scrape off any thinset above that 1" strip, otherwise it might hold the larger tiles off the wall more. No problem if you scrape it off a little short of the tile, though. Those notches would act like a little bridge underneath to hold it up just that extra amount. The hassle is, you end up waiting a day in between. this often isn't a big deal with a DIY'er, since time might be contrained. You can set it all at the same time, but be prepared to dig out some thinset between the tiles before you can grout it.
Another technique that can work is to take some HardiBacker and split it. Sounds tough, but the stuff is made up of layers, and you can split it off the desired thickness (or close!). Takes a bit of practice, but it can be done in a strip like that.