For clarification when you look at the site Mick posted you are in the Lincoln Zone right on the line between Lincoln West and Lincoln east. See this link:
You are obviously in the Roswell BLM Field Office area.
I think what the BLM was talking about when they mentioned a statewide repeater system is exactly what Mick mentioned. I would not think they were alluding to another system such as a statewide fire or law enforcement system. The BLM state office in Arizona has a statewide law enforcement net and is used by BLM Rangers no matter what field office area they are in. So it is possible that they were alluding to some other system we don't know about. In what context and venue was this told to you?
I lived in New Mexico during my career with the U.S. Forest Service and the BLM radio systems have not changed much since. I think they were using burst tones to access repeaters then. Yes it has been that long since I lived in NM, as it was 1978 through 1981.