USA was put in Group D to increase their chance of being the last co-host standing
Group C got skipped so that co-hosts were in different brackets, but why USA specifically moved into the later groups? I think it's because even if the USA doesn't progress to a later round than their co-hosts, they would at least be able to claim they were the last host to be knocked out (so long as they didn't finish 3rd in their group) to satisfy egos.