I see many reasons not to put them together.
One is that they all have different food requirements.
Another is that they don't come from the same region so what is normal flora (germs) for one species isn't normal for the other, in other words one species carries germs that are normal to them and don't cause illness but it could make the other species sick.
One species could become more aggressive than the other & when the sulcatas are larger they can harm the smaller tortoises- even by accident just because of the huge size.
If it were me, I wouldn't do it.
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PHRatz