Hi there. Sure, that is totally possible. You don't have to buy a Crmble License for every Trello workspace user. In your Crmble Team section (bottom option of Crmble's main menu), please open the "Plan" tab. There you can choose the number of licenses you'd like to purchase as shown in the screen recording below. After the checkout process, please reload your Trello board to refresh.
Once your licenses are available, all you have to do is assign them to the Trello users of choice.
Hope this helps. If you need further assistance, please send us a message using the support chat bubble inside Crmble or schedule a 15min meeting with us.