All objects in DISE can be combined together. A combined object will display one object inside the other by using one of the objects as a mask for the other. This allows you to for instance create a text with a video showing inside. By default, some properties will not be applied to merged objects, such as shadow and transparency - selecting the object, these features are grayed out in the Object Properties.
Select the two objects you want to combine, and either right-click or click the Group icon in the toolbar and select Combine objects.
You can at any time select Split into objects to revert back to the original objects.
Use alpha from
Alpha texture options
Invert alpha