Prepare your grill so that it is 250 to 300 degrees.
Cube the three types of cheese into about one-inch pieces. (Make sure to use blocks of cheese instead of shredded; it melts better.)
In a foil, eight-by-eight-inch pan, add the cheeses, Rotel, black beans, taco seasoning, garlic and salt, and stir to combine.
For the steaks, pound them to about one-half inch thick, and season them liberally on both sides with steak seasoning, pressing it into the meat.
Once your grill is ready, place your pan of queso on a lower rack (we're going to cook the steaks above it). If you're using a standard grill, place it so it's getting indirect heat. Close the lid and let the queso cook for 20 minutes.
After the 20 minutes, stir the queso. It probably will only just be starting to melt together. Place the steaks on a grate over the queso so that the juices can add flavor to the queso. Again, close the lid.
Check the queso every 20 minutes, giving it a good stir, and turn the steaks when they have good grill marks on one side.
Once the queso is melted and the steaks are done (after about one hour), remove it all from the grill. Be careful not to let the cheese overcook; it will get lumpy and separate if you do. Let the steaks rest for five minutes, and then slice them.
Serve the queso and steak over chips with your favorite nacho toppings.