Been a bit since I've put up a Nixiris. Get ready for the wall of text.
The Nixiris no longer have a home world of their own, hence why they all live on stations that float through space. Each station is equipped with very sophisticated communication systems set up as a "web" between all the other stations. Thus messages are sent and amplified from station to station, and also piggybacked off of trade ships sent from orbiting stations.
Any station that finds an inhabited world with sufficiently advanced technology will attempt to make contact and set themselves up as a permanent orbiting station. This will usually draw out the more adventurous members of the worlds inhabitants, whom the Nixiris welcome onto their home, and occasionally into their families.
Though natural crossbreeding is impossible, their advanced technologies in genetics does allow for a non-Nixiris parent to donor genetic material. This will always result in a Nixiris Child, though small mutations may occur. Normally just an odd eye color, strange ear shape, or different number of toes/fingers. The fur of these children are ALWAYS devoid of pigment, as is the norm for the race.
If enough of the populace of a station wish to continue the journey through space then a new wandering station is built, crewed and sets off to begin the process anew.