The GHS is a spinoff of the GWS series. Here's the reading order for them if you would like to read them together.
GWS: Book 1, Prince of Wolves GWS: Book 2, Blood Rites GWS: Book 3, Just One Drop GWS: Book 4, Out of the Dark GWS: Book 5, Beyond the Veil GWS: Book 6, Fate and Fury GWS: Book 7, Sacrifice of Love GWS: Novella 4, Sacred Silence GWS: Novella 2, Resounding Silence GWS: Book 8, Luna Mine GHS: Book 1, Into the Fae GHS: Book 2, Wolf of Stone GWS: Novella 1, Piercing Silence GHS: Book 3, Jewel of Darkness GWS: Book 9, Den of Sorrows GWS: Book 10, The Burning Claw GHS: Book 4, Wolves of Wrath GWS: Novella 3, Forgotten Silence GWS: Book 11, Tears of the Moon GHS: Book 5, Wolf of Sight
GWS: Book 1, Prince of Wolves
GWS: Book 2, Blood Rites
GWS: Book 3, Just One Drop
GWS: Book 4, Out of the Dark
GWS: Book 5, Beyond the Veil
GWS: Book 6, Fate and Fury
GWS: Book 7, Sacrifice of Love
GWS: Novella 4, Sacred Silence
GWS: Novella 2, Resounding Silence
GWS: Book 8, Luna Mine
GHS: Book 1, Into the Fae
GHS: Book 2, Wolf of Stone
GWS: Novella 1, Piercing Silence
GHS: Book 3, Jewel of Darkness
GWS: Book 9, Den of Sorrows
GWS: Book 10, The Burning Claw
GHS: Book 4, Wolves of Wrath
GWS: Novella 3, Forgotten Silence
GWS: Book 11, Tears of the Moon
GHS: Book 5, Wolf of Sight