Set references to separate tabs to Absolute?

See attached example containing no confidential information.

Is there a way to set cell references to absolute ONLY if they're references to another worksheet in the file? If I set all cell references to absolute and copy/paste the formula as needed on worksheet "RESULT", column E's calculations are broken. If I set all cell references to relative & copy/paste, I progressively lose cell references row by row.

And unfortunately, the actual document I'm working on is massive & already established, so the solution isn't as simple as setting the absolute references by hand. I'd have to carefully examine hundreds of formulas and add the dollar signs myself.

Thanks in advance!