Yes, you can do this using the “Include file from other project” option within the Add Files menu:
One convenient way to set this up if you're planning to use the same files across multiple projects is to organize things as follows:
.sty, graphics, etc.
You will now be able to used the linked file in your “child” project.
If you’ve modified the original copy of the files in the parent project, remember to click on the linked file in the child projects and then “Refresh” to pull in the changes.