One Engram to learn multiple Items

• 

  Create your Engram as usual and point "Blue Print Entry" to your main item

• 

  All additional items don't need an engram: just point "Engram Requirement Item Class Override" to your main item

And that's it. All your items will now be available for crafting after learning that one engram. Note that this will probably not work for items if they should be crafted inside the player inventory.