If you create a group in your EndNote library, you can share it with colleagues that also have an EndNote account.

Then it will show in your desktop library, and you can add citations to it alone, or from your existing collection.
It is possible to use EndNote and Zotero together or to share Zotero libraries with colleagues using EndNote (or vice versa). Both programs can read and write a standard citation file format called RIS, which means references can be converted back and forth with a few clicks.
Zotero to EndNote
To save your Zotero library for importing into EndNote:
EndNote to Zotero
Follow these steps to export your EndNote library for use in Zotero.