Grav page list in Gantry particle

Hi All, I'm just discovering Grav and installed Gantry. These two thing is super cool. I would like to create a particle in which I can select a page from a dropdown select. I think this would be the best way to integrate Grav and Gantry really. Use case: Gantry Helium theme, Basic outline. I like to add this new particle to all of the sections and I would like to define which page have to be displayed in the section. (now I can not do that any of the particles). I know it seems to be a Gantry question but I think I have to create some PHP code to read out Grav pages list. Any suggestion about the above mentioned case?