How to get nearby objects

This is my scenario: i developed a furniture configurator based on “click to add model” mode; user simple clic on icon, then choice an object from catalogue; then user can add others objects by clicking on icons over previous object (up, down, left, right, front or back). The 3D objects are glTF models.

Now, i’ld like to know how detect, after selecting an object on scene, what is the next object along a given axis.

Any idea or suggestion?