But, there is another way. This is assuming that all fonts are on all Macs involved, and in the same location on each Mac, /Users/Shared/Fonts is a good place.
Save the configuration of FEX (File: Configuration: Save), and give it a meanful name for the set(s) you want to transfer. This saves the complete current configuration of FEX -- prefs, font search rules, sets, and smart sets. But there isn't a way to export parts of the configuration; it's all or nothing.
It turns out FEX saves a Mac OS X package folder with a .fex extension, with plists for each of those four components:
- com.linotype.FontExplorerX.plist
- FontRequestRules.plist
- Sets.plist
- SmartGroups.plist
The root of the plist is just an ordered array of the sets. In a text editor, sets will be enclosed by <dict>...</dict> pairs. Delete all but the set(s) you want to transfer to another Mac. Save the plist. I deleted the other plists to be safe, so some user doesn't accidentally mess up their prefs or other sets. Yet, the next step offers a choice of what to import.
So, copy that config package to the other Mac. Double-click it to open it in FEX. You only want to import either Sets or Smart Sets, depending on what you deleted earlier. Then, make sure you choose to Merge with current configuration.
There you are -- the set(s) are transferred to another Mac (or many others). No reading a text file to recreate the set. No copying redundant copies of the font files around.

