Selecting connecting objects to hide

 From:  Lang (LANGLEY)
Hi guys

I'm trying to select connected items as my model has two almost touching objects that have been extruded and I want to amend one of them to be slightly different on the inside. I've played around with this for a while now and have been through the reference material but can't find a way of hiding parts of my object without selecting the whole thing. Is there a way of selecting the whole object from just picking up an edge or one side of the object?

I'm sure its there but i'm just missing it.

Thanks guys, Lang.