Yes there are a number of ways to do this.
1.If you transfer the file as a GPX directly to the XT internal memory then the waypoints will appear as favourites.
2.If you transfer them to an sd card in the XT then you have to go to favourites top left hamburger Icon and import them into favourites from the sd card.
This works well for a smallish number of waypoints say <30. There are likely other favourites in that folder and larger numbers become unmanageable
3. For larger numbers of waypoints create a POI file using POI loader (Free from Garmin) you can then create your own categories of POI's and load these into a route or as a destination on the fly. This can enable things like proximity alerts and custom Icons/sounds for these POI's