Tool | Combine Appearance
This command applies appearance properties of one part on successive clicked or selected parts.

1. Click Tool | Combine Appearance

Here one part is set to transparent or X-Ray mode.

2. Click a part in the model  from which the appearance to be copied

(Click first in transparent part which is going to be applied on other parts)

3. Click any other part to which the copied property should be applied.

(Clicking on other parts, they are also made to be transparent appearance)