Thank you @Jennifer_Dungan and @bjoern__koth for your explanatory replies.I will use all your suggested options to make it work. The appendvisitorId has partially worked for us when used for a different project. 

Dear Experts,Need your expert opinion on a situation. Consider a Parent Content Website ABC.com where mostly all paid campaigns land onto and further it routes the users to different products purchase path. From the content website ABC.com the visitors can go to the subdomain xxx.ABC.com and purchas...