This, in my humble opinion, would be a bad idea. Cross sub-domain tracking is one thing and can be done to good effect if needed, but this situation might be better served with a qualified Goal, maybe with RegX or filtered view in Google Analytics (GA). To my knowledge, you can only use one GA tracking code with Webflow that is universal for the entire site, not just individual pages. I think you could add other GA codes via Custom Code, but I still think it's a bad idea even if possible.
Note: This was confusing due to the use of the term "Tracking Code" is used for normal GA installation on a website. The Experiments code is a different, additional code in that it tracks the progress and results of the Experiment (A/B & multivariate page testing) within GA, it's beyond the normal GA code.
Update: Lino and I are sorting this out in PMs.
Good Luck & Take Care,
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