In the advanced roadmap, I have created a issue type called Goal that is one level above the Epic type.
In this case, under the view of advanced roadmap, I want to display one Epic issue under two different Goal issues at the same time, is it possible?
If it is impossible, what about I create another issue type that is the same level of Goal, and display one Epic issue under those two different types of parent issues?
Unfortunately, this is not possible. A ticket only has one parent. The best option would be to create a separate epic for each goal.
The other option is to use links, but they would only display as links and not under the parent when you expand the parent, but you can see the relationships with the lines.