Can i use family client codes in internet trading with single login

i have 5 client account's with my broker , but he says that i have to log out and login in the code to put order, is there any broker who can map my family account and i can put orders in all accounts thru single log in.

These are safety measures inbuilt in the software to protect you from error or malpractice, and I feel they should be adhered to. In case a site provides you with an option of single login, you will still have to fill in different IDs to carry out transactions.