WarcraftRealms.com

I recently started a European WoW account while still maintaining a US account. Both accounts have the same name. Since I started logging on to the European servers my US census data gets wiped. Likewise when I log onto US servers my euro data gets wiped. This has forced me to upload data every time I switch from US to Euro or vice versa. This isn't practical since I'm switching a couple times a day. Is there anyway that both US & Euro data can be saved to the same file and uploaded at once?

Nope, not since you used the same account name for both your US and EU accounts. Had you used different account names, then yes, but since it's the same, then it's not possible.