As long as you have two lines of service and you will be the account holder of record for both lines. It does not matter if they are on the same voice rate plan but if you are not the Account Holder and this is a new activation, you will have issues.
If this is an upgrade to an existing line and you are a Retail Authorized User, your local Apple store may choose to allow you to pick up both upgrades. Please note the offical Apple policy is that the Account holder must be present.
Call and ask.
Dave