Yes. You can own as many Haystack cards as you want and choose which ones to share.
To add another Haystack card:
Tap on the '+' icon at the top right above your card
Type in a new email address for the new card you want to add and follow the prompts
Your new card will appear and we'll send you an email to verify that it belongs to you.
Note: Each card needs a separate email address. If you want to create multiple cards using same email address, this is one of the features available on our paid plans.