It is possible to have different styles in one model. I offered the following response to a similar question in an earlier post over this past summer. Blueprint Style in Layout
The style of a model should be defined in one of your SketchUp scenes which can then be exported into a Layout file. Your model can have various styles portrayed and each of these can be shown in the scenes that you place into Layout.
In SU, go to Windows->Styles; then in the Styles dialog box that appears, click on “Assorted Styles” just below the “Select-Edit-Mix” tabs and then select the Blueprint style in the box as shown. Once the style is identified in a specific SU scene, save the model and then export the scenes you want to see to Layout. Your Layout window will be set accordingly.