You can easily manage that by configuring command line interface to interact with AWS such as your security credentials and the default region, profile name.
To overcome the difficulty, Create a AWS config file ~/.aws/config with following lines:
[profile profile_name_of_account_name_A] aws_access_key_id = account_A_access_key aws_secret_access_key = account_A_secret_key [profile profile_name_of_account_name_B] aws_access_key_id = account_B_access_key aws_secret_access_key = account_B_secret_key
Now, simply run a command like:
eb init --profile profile_name_of_account_name_A
Click here to know more about configuring multiple AWS accounts to use with command line.