The intent here is good, but I don't think you can do that? Can you define "lobbying" in a way that encompasses all (or at least most) of the bad activity but doesn't encompass acceptable activity?

What even is lobbying? A broad definition would include most any communication with a policymaker, a narrow one would exclude lots of activity that is obviously meant to influence policy.

If you want to reduce the influence that moneyed interests have over politics there's only one answer: take their money away.