embedded object position and selection

[jkushwara 0]

If I've imported 2 objects - one an outer shell mesh and the second a custom infill mesh  - is there a way to  - 

 

 1) Prevent any auto positioning of either mesh  - they need to maintain the original position as modeled. In this case, the infill mesh is centered in the outer shell mesh. I need to be able to group               them and position both on the print bed together. 

 2) easily select one or the other ? With the infill mesh completely embedded inside the outer shell mesh, I can't seem to select it. 

 

adding an image for clarity. The inside part should be floating in the center of the outer shell part. 

Edited October 26, 2018 by jkushwara