If all dealers own their individual websites under individual domains
but not under the tier1's sub-domain, I think you need to configure the
cross-domain tags and deploy in their individual websites/pages, sorry I
don't have much experience & further idea on it.If you are asking about
the exit link on tier1 website to other dealers webpage contains
promotion, you may just check the "exit link" and the metrics, e.g.
pageviews, visits.E.g.There is a webpage called T1Prom in Tier1
websiteThe webpa...