Khan Kids--how to adjust for different reading/math levels

Hello!

I'm a special ed teacher looking looking into whether I'd be able to use Khan Academy Kids for independent work in the gen. ed. classroom for some students I'm working with. Some of these students are at different levels for reading and for math. Can I do any of the following:

Set a student's reading and the math levels to be different grade levels
Tell the Learning Path to only do reading or only do math (which would
allow me to get the same result with two different results)
Otherwise, does the Learning Path only adjust within the grade level
it is set to (e.g. higher vs. lower kindergarten work for both
subjects), or would it automatically figure out that a student needs,
say, kdg reading work and 2nd grade math work?

I'm hoping there's a way to get the learning path to do one of those things, so that I don't have to rely on assignments that disappear every 2 weeks, and also there's the risk that they'd try the learning path and see problems that are way too easy for them in their stronger subject and feel negatively about the app or about themselves. Any ideas?