documentclass[]{scrbook}

KOMAoptions{twoside=false}

usepackage[hidelinks]{hyperref}
    hypersetup{pdftex,colorlinks=true,allcolors=blue}
usepackage{bookmark}
    bookmarksetup{numbered,open}
usepackage[toc,acronym,nopostdot]{glossaries}
usepackage{siunitx}

newglossary[nlg]{nomenclature}{not}{ntn}{Nomenclature}

makeglossaries

newcommand*{Agroupname}{Symbols}
newcommand*{Ggroupname}{Greek Letters}
newcommand*{Sgroupname}{Subscripts}

newacronym{rpm}{rpm}{revolutions per minute}
newacronym{gdt}{GDT}{Geometric Dimensioning and Tolerancing}

newglossaryentry{geo}{
        name={geometric},
        description={relating to geometry, the branch of mathematics...}}

newglossaryentry{pressure}{type=nomenclature,
    name=ensuremath{P},
    sort=a,
    description={pressure (si{newtonpersquaremetre})},
    first={pressure (ensuremath{P})glsadd{pressure_g}},
    see=[Glossary:]{pressure_g}}
    newglossaryentry{pressure_g}{
            name={pressure},
            description={a continuous physical force exerted on or against an object by something in contact with it}}

newglossaryentry{density}{type=nomenclature,
    name=ensuremath{rho},
    sort=g,
    description={density (si{kilogrampercubicmetre})},
    first={density (ensuremath{rho})glsadd{rho_g}},
    see=[Glossary:]{rho_g}}
    newglossaryentry{rho_g}{
        name={density},
        description={a material's mass per unit volume with units si{kilogrampercubicmetre}}}

begin{document}

frontmatter

glossarystyle{listhypergroup}
printglossary[type=acronymtype,title=Abbreviations]

glossarystyle{listhypergroup}
printglossary[type=nomenclature,title=Nomenclature]

mainmatter

chapter{Test}

gls{gdt} and gls{rpm} are abbreviations. Gls{geo} is a glossary term. Gls{pressure} and gls{density} are nomenclature terms.

glossarystyle{listhypergroup}
printglossary[title=Glossary]

end{document}