I think it will have to be one contact list on your phone used by all. Read this:
Add and Edit Your Contacts to the Alexa App
Sync your contacts to the Alexa app to communicate with friends and family using Alexa calling and messaging.
To add or edit contacts for Alexa-to-Alexa calling and messaging, update your phone's local address book and then open the Alexa app. Contacts from your address book who also use Alexa Calling and Messaging automatically appear in your "Contacts" list in the Alexa app, with the same names from your address book.
If you have multiple members within your household, your Alexa contacts are shared across all devices registered to that account. However, in the Alexa app you can only start conversations with your Alexa contacts.