Did a general in the SS outrank a Wehrmacht general, for instance? Would it work like that?
In short: No.
First, some vocabulary. The Wehrmacht was the German Armed Forces in general, the most comparable force to SS troops would be the Heer, the Ground Force of Nazi Germany. As far as I know, the SS had no own Naval and Air Forces, but would use supportive forces from the Luftwaffe and rarely fought near or even at sea. It was a ground force.
Next, we are talking about the Waffen-SS here, which is part of, but not to be confused with, the SS (Schutzstaffel) in general. The SS at large was the protective squadron (that is the literal translation of the name) of the Nazi Party, the NSDAP, and was thus an ideologically charged paramilitary - their and the army's comparisons to the SA (Sturmabteilung) would be one of the factors that played into the Night of Long Knives in 1934, when the right wing of the NSDAP eliminated the left wing and the SA leadership.
The Waffen-SS was a wing of the SS intended for military frontline combat.
Okay, all that aside, the Waffen-SS was pretty much a part of the Ground Forces. They were not immediately the "super evil elite" that we might imagine nowadays when thinking about the Waffen-SS, but they increasingly were tasked with ideological objectives - most of which having to do with the Holocaust.
So, to think that the Waffen-SS was the magical elite of the Wehrmacht/Heer is wrong in that regard.
Okay, now to quickly answer your question: The ranks are equal. Much like an Admiral is equal to a General in many militaries, just from navy and army respectively, an SS-Oberst-Gruppenführer would be the equivalent of a Generaloberst des Heeres. And much like Generalobersts, they commanded armies (like J. Dietrich commanding the 6th Armored Army) or even army groups (like P. Hausser commanding the Heeresgruppe Oberrhein).
They did not have the competence to command each other around. An SS commander of higher rank could however give a Wehrmacht commander of lower rank orders and vice versa if the situation demanded it.
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