Yes. In fact in general if those lines are with other people you shouldn't have them associated with your T-Mobile ID.
What you can do is to have each of the other people to sign up for a T-Mobile ID for the line that they use. In that way they'll have access to the number(s) associated with their T-Mobile ID and not any of the other lines.
Do note that during the beta, those new T-Mobile IDs won't be able to access or use the DIGITS application until if/when we expand the beta to include other people.
This thread was the product of our fantastic collaborators during DIGITS Beta! As many terms have changed and bugs have been exterminated since the Beta launched, the information here may no longer be accurate. If you still have a question, please search our active threads or ask a new question in the DIGITS space!