Use either the ctrl-click option on the model or in the lower right corner next to the family selection icon is a little grey upside-down triangle, click that and you can select the meshes by name. Then once selected do as Stephen said and go to solo mode (green button in the middle of the forward object/back object icon which is to the right of the triangle descibed above). This way there is no reason to ungroup the model and go through the hassel of regrouping it all again.