Reappearing Stock Model

If I model the raw stock in Solidworks and import it as part of the assembly, then make copies of the assembly for further ops, every time I switch to a different op, or to the tree, or back to the activities view, that solid unhides itself in each copy of the NC assembly.

 

Is there any way to convince these solids to stay hidden unless I, as the user, unhide them?

 

Many thanks.