Actually the three stories are connected. The first one in the series is SG13 Suicide Squad
(pairings are established here), followed by The Stargate Murders
and the last one is The Guardian Angel
. There are crossovers due to the nature of the stories. I do have to say this. All of them are extremely long. It should take a few days to get through them all unless you want to spend a whole day sitting in front of the computer reading them all in one go.
Luckily, I was a high school student when I was reading this.