What an awful situation to be in...
A perfectly balanced workplace is an unattainable goal, and a fair one is more of a dream than reality. Right now you have two groups of people working in the same environment, let's call them group A and group B, where group A is supervised by group B, while the reverse isn't true for the same or a similar set of activities.
Given that the only difference (we know of) between the two groups is a biological characteristic, I'd agree that the situation reeks of discrimination. However I don't think, at least from the available data, that we can safely conclude the management's behaviour is unfair (and potentially illegal).
What you need to do first is gather more data. A good place to start would be discussing your observations, in an as much an unbiased way as possible, with colleagues you feel comfortable with. Get at least a hint of confirmation that there are others out there who noticed the behaviour(s) and reached more or less the same conclusions as you.
Regardless of whether there are colleagues you feel comfortable enough to discuss the matter with, the next step would be to gather hard data, any kind of documentation that supports your observations. Since the behaviour manifests itself in an organizational manner, I think you have good chances of actually finding paper documentation that describe the possibly unfair hierarchy.
Assuming that you've found at least another colleague that agrees with your conclusions, and/or hard data that hint/support that there's something fishy going on, you need to start debating whether to report the situation higher up the hierarchy chain or not. From my brief time in education, I'd suggest looking into your local school board, relevant professional association(s), local deaf people associations, and even NGOs that focus in fighting discriminatory behaviours.
Lesser options to report the situation would be local or even national news, but be prepared for a ruckus, and political organizations, that in my experience would jump at the opportunity to present themselves as leading an anti discrimination campaign.
Whether to actually report the situation or not, and whether to do it anonymously or eponymously is completely up to you. Obviously reporting it eponymously would be the option with the more chances of success, but also the option with the larger impact on your own career. It's a personal decision, and I'm afraid I can't advise you further one way or another.
Fortunately I haven't had much experience with discriminatory behaviours in the workplace, but from what I've seen I can tell you that it's quite easy to masquerade them as valid management decisions. An easy excuse to the situation you're describing would be that hearing colleagues aren't actually supervising the deaf ones, but the two groups are coupled for the activities the deaf colleagues are in charge to help the deaf colleagues deal with external parameters, like contacting parents, or whatever/whomever else outside the school (it's a hearing dominated world, after all).
One thing to keep in mind is that usually discriminatory behaviours stem from deep personal bias, and it's unlikely that they only manifest in a simple organizational matter. If the bias is there, there will probably be other traces of it and behaviours like the one you're describing are probably going on for a while.
Arm yourself with as much evidence as possible, hard data is essential, and... good luck!