Question regarding different accounts with the same ip address

The rules say 1 account per ip address but its best to submit a ticket. http://www.steamgifts.com/support/new

As far as I'm aware if you tell cg about the situation it is fine.

I guess it's fine if you contact the staff to let them know whats going on. My brother lives in another city, but when he came to my house, we sent an e-mail to explain the situation. And... well, we both are still here. xD

From the FAQ:
Only one account per IP address. If you have someone else in your house using SteamGifts, please give the admin a heads up by submitting a ticket on the Support Forum.