I have set up a plan/advanced roadmap that includes multiple JIRA projects. I have dependencies that cut across multiple JIRA projects and these dependencies are identified at the JIRA epic level. 
When I look in advanced roadmaps, I can see the dependencies within one project, but I can't see dependencies between projects.

Can I use advanced roadmaps to visualize dependencies across projects by adjusting settings? Is there an add-in that can do this?
I have looked at dependency mapper for JIRA and link map, but it isn't clear to me whether these can actually visualize dependencies across JIRA projects.