I assume you don't mean a new domain, but simply a new landing page on the old, recognized domain (which takes care of higher quality score and lower ppc).
If so, the simple answer would be to put ppc pages in a new directory and disallow the directory in robots.txt for all robots EXCEPT 'AdsBot-Google', which should be able to crawl the page(s).
You can achieve the same per individual page by using meta tags.

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