Battlenet - Multi Wow Accounts

I currently own multiple accounts of WoW. Meaning i can play log in the game with multiple characters at once. I know its geeky but i like talking to myself :P

My question:
If i create a Battlenet account and merge ALL my wow accounts under one battlenet account. Does that mean i am only able to log one WoW account at a time due to the log on details being my email/pw. Also.. as most of my accounts have between 6-10 characters for my main server. Does this mean i will breach the cap limit of accounters per server?

Or

Do i need to make a separate battlenet per WoW account?

Would like a GM answer or someone who knows their stuff.

Thanks