I have a history project in which there are multiple points of view. Each point of view I have in different folders, but there are many occasions in which the same scene (the same document) corresponds to both one character and another (even several at the same time), when both characters are together and live the same thing.
I was wondering if there is a way that I can modify the same document, but have it appear more than once in the binder. As if there were ‘two linked documents’, in which if I modify one, the other is also modified.
So far what I’ve done has been to manually duplicate each scene in which there are several POVs and put each one in its corresponding folder (and modify both when there are changes), but if it could be done automatically it would be much more comfortable.
Thank you for your time 
Hi Ainoa.
Perhaps look at this post where I explain how to use bookmarks for documents’ proxies.
The term the OP used throughout the thread was “replicant” (from some other software’s terminology, if I recall properly), but I otherwise believe that could potentially be a viable solution for you.
Have you checked the ‘$Include’ Placeholder ?
Hey, um, I know it’s a bit late, but I tried this method you said and it works amazing! Thanks for telling me 
Is there any way to have a document reside in one folder in the binder, but have a link to it in another folder? For example, to have a character sheet in a folder for a story and have a link in a folder for a town. Like Windows shortcuts for a file in a different directory.
I’ve merged your request with an existing recent one, on this same matter. In addition to the above discussion, I’ve also written a bit on how you can achieve similar capabilities. Briefly, Collections and Bookmarks (especially document level bookmarks which link two items together directly in the inspector sidebar) solve a lot of the reasons for why you’d want this, and the <$include> compile placeholder solves another huge chunk.
For example in your case, establishing a relationship between a character and a town as background material is exactly what document bookmarks are designed to make convenient.
Yes. I have a folder called Characters.
The folder has the name of each of my major characters (around 70 per novel).
Highlight the name of a character, and select Link to Document from the contextual menu. (You should have created at least one character sheets beforehand.)
Choose the respective character sheet by manoeuvring through the contextual hierarchy.
When done with your Characters folder, drag it to Project Bookmarks, the second tab in the Inspector. (I’ve set links to open iin a Quick Reference window under File > Options.)
So, working with the Inspector on, you have access to your character sheets which are basically a mouse click away, since the names appear as internal links in the Bookmarks preview screen below Bookmarks.
The aforementioned setup is different to what you’d find in the manual, but works most effectively for me. (I even have my characters in a separate Series project, because many appear in different books, though not all. Linking across projects is handled differently, though—but still easily managed.)
Linking about 70 character sheets this way is about an hour of finger gymnastics and you have it forever and can grow your list on the fly as you please. Adding names and links can be done in the preview pane, once you list is in place in bookmarks.
You could also create character link sheets with POV’s on one sheet, New York Characters on another, Criminal Mob etc with a link to each character on one document. Now place these in Project Bookmarks and can quickly narrow down a link to a character and click the link to open in a QRP. This could be done with locations, world building etc. A simple keyboard shortcut of CTRL + 6 flips between document and Project Bookmarks.