Groupings (objects in hierarchy) with reactor (water)

[tomcat_ace]

Hi,

 

I'm working on a school assignment where i have to make and animate a 3D logo.

 

So what I have here is a modeled macbook with like 60+ buttons and ports made according to its original design, as well the screen with a fake image. Everything here I did I used architectural and arch mental ray as textures.

 

The 2 laptop panels (upper and lower) are IK'ed with bones, it's made so it's easy to stimulate realistic joint effects. Every single object is linked in some way.

 

as well i have a reactor water object made linked to a plane

 

so what I wanna ask is, how can i join all the laptop objects into one so that I can assign them a mass and not fall apart when dropped (the thing won't even allow me to create a rigid body, it says error..Help)?

 

thanks

 

 

reference image follows