Hey OP, I will give you my usual spiel. We definitely want you to know what the composition of your "Xaxax Bars" are. We would love to be able to answer this question for you. It's simply not possible, so we typically close drug identification threads without an objective that can actually be achieved. What good does it to a person to have one thousand questions answered if these questions inherently go on for infinity?
We could tell you for instance, that Clonazolam, a common, potent Benzodiazepine sold over the grey market has been found in bars of this variety in the past. We could tell you they could be Bromazolam. Then, there is always the possibility that they are just Alprazolam right? The issue here is that we are dealing with the personal safety of both yourself and anybody else who happens to be reading your thread. When a single milligram of a substance can literally mean the difference between life and death, it is to nobody's benefit to speculate errantly.
You have options. Firstly, you can send a single piece of one of these bars into a testing laboratory and have them tell you straight up what is contained therein. The only problem is, you then need to know the exact proportion of a given chemical is contained within each bar. These are "professionally done" in most cases, but that doesn't mean there cannot be presses that are more potent than others.
With this sort of thing, you have to use common sense and reason. Realistically, you are going to answer your question in a more constructive way than anybody else will be able to. This means taking a small portion of one of these bars and being mindful to how it affects you. Your trials on yourself are going to give you far more usable information regarding how these pills will or will not fit into your life.
Otherwise, you'll just speculate endlessly. Start low, go slow and don't mix with anything that will muddy your subjective experience. Even when you have a benchmark in mind for how this stuff works upon you, you still need to tread carefully. The aforementioned "hot spots" along with the possibility that you could have pills from different production runs in the same packet. You have to use common sense to be safe.