Figuring Out My Reading Groups

I have finally finished my Read 3D assessments on all of my kids but one who has been absent. Since I now have their reading levels, I am able to group them according to ability. We are required to have four reading groups and, luckily, my kids all fit into four very even groups... all but two. My top group is all at a level K, while I have a student at an M and another at an N. Now what do I do?

During my student teaching, the students in my top group weren't all on the same level but their levels were definitely a little more similar than this group. A K to an M may not seem like much of a difference but there really is a huge jump between those levels. So how do I teach these two students on their levels without having five reading groups? I owe it to my students to teach them on their level--I don't think that they would make much growth by reading way below their levels.

The only idea I have at the moment is to put them in their own partly-independent group. Since they are reading on such a high level , they can read the text independently (for the most part) and then we will meet for about 10-15 minutes in the morning while other students are completing their morning work, and then they will spend the time that they would normally be meeting with a reading group doing an independent assignment on their text. These assignments will use higher-order thinking skills and will show their comprehension and their understanding of key vocabulary.

I am going to do more research to see if there is a better way to do this, but this is what I am currently planning to do! If you have any advice, let me know!