(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?
(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.
Heather,
Is this similar to collapsing a grouping band and showing all activities in the same row?
No idea if Visualizer can do this, but I've certainly used Turbo-Chart to create custom Gantt chart views linked to my P6 project.
NOTE as a disclaimer that I am co-founder of Turbo-chart