If you want to read the stories in chronological order, you have to start with the Prey series, then read the Virgil Flowers books and the Kidd and LuEllen books intermixed with them. These are NOT three separate "universes". Both Virgil and Kidd and LuEllen get introduced in different Prey novels and the characters appear off and on in other Prey novels. It's best to just read ALL of these series in the order they were published.

By the way, I finished Masked Prey a couple weeks ago and it's another good one.