How to remove individual steaks from a lump I mistakenly froze together?

Your best bet for preserving quality (and safety) is to re-seal the bag, then leave them in the fridge for a bit. You want them to thaw a little, so you can pry them apart. Its safe to re-freeze after this (as the meat never entered the danger zone, indeed it probably never got above ~30°F). There will be some quality loss from the partial thaw-freeze cycle. I recommend waiting to do this until you'll be cooking at least one of the steaks.

Now, how to freeze them:

Freezing in vacuum bags isn't special. Just like with freezing in ziplock bags, freezer paper, foil, etc., you need to freeze individual servings individually. If you want to economize on vacuum bags, you can try one of:

• Wrap the steaks in plastic wrap or freezer paper to freeze. Once frozen, transfer to vacuum bag and draw vacuum.
• Place two steaks in the bag next to each other, separated by ~1in (depending on thickness of steak, you want the bag to be able to conform to the shape of the steak). If you're using an external vacuum machine like a FoodSaver (as opposed to a $600+ chamber machine), the steaks may be pulled together as it sucks out the air; press your finger down on the plastic between them to keep them apart.
• Separate steaks with freezer, parchment, or waxed paper (you can try plastic wrap, but they may freeze together anyway...) in one bag. You can stack them on top of each other, or put the immediately next to each other (without the 1in space), or both. Freeze after sucking air out.

There is a disadvantage to stacking things thicker to freeze (as in the last suggestion): generally speaking, the faster you freeze something, the more quality is retained. And of course the thicker it is, the longer it takes to freeze through.

If you're cutting from rolls, remember that each time you open and re-seal the bag, you're going to cut off an inch or so of plastic, depending on your vacuum machine. Cut the bag big enough to accommodate this.