This exact functionality is not something that Altru can currently do. We can add an add-on that cost $0.00 to use when entering a comp membership.
 
  1. From Memberships, click Add-ons under Configuration. The Add-ons page appears.
  2. On the Add-ons page, click Add. The Add an add-on screen appears.
  3. Enter the name of the add-on
  4. In Add-on type, select whether the add-on is a benefit or an additional member
  5. Click Save
  6. On the Prices or Levels tab (the tab name will depend on your program configuration)
  7. Under Add-ons, click Add
  8. Select the add-on and assign a price
  9. Save

We encourage you to vote on this idea in our community as this is an opportunity to have a voice in the product development process. Our Product Management team uses a variety of methods to determine new features in Altru, and the ideas in the Community is one way they do this, so your vote helps Product Management prioritize the new features that we put into the product.