The applications section of the data sheet indicates tying Vin, Vout, and Share together - along with TR/SS. It shows how to calculate the Rfb but doesn' specifically say how this should be wired among multiple units. The application example in Typical applications shows two paralleled units but each with their own Rfb based on the table of recommendations for a single device.
So what is recommended?
Do all the Rfb pins of sharing units get tied together and brought through a single Rfb to ground as implied in the sharing section, or should each unit be set up with its own Rfb as shown in the typical applications section.