Hi,
This falls under the “wishful features” category, but I’d love to be able to apply scrivener links to a notecard, or be able to click on a photo card to take me to a specific text file. 
If there’s a way to do this I haven’t thought up, please do inform 
Continue to love the software!
There’s not really a way to do this, as synopsis text is not a rich text field. What you could do is drag the documents you want to link to into the first document’s references list (in the inspector). It will take you an extra click, of course, but you could then select the index card in the corkboard, for instance, and click on the linked reference in the inspector to open the text file.