Since you are mentioning that you want a group of cities, you can first create a group of cities dimension with the required cities. Then place this dimension in the rows and you should have what you need. Let me know if this is not what you are looking for.
Thank you for the response. That's one of the ways I want to approach it. Cold you tell me how I can create a new dimension out of the values in the existing dimensions?
The other way is being able to select any cities for the upper chart and any cities for the lower chart, where the two charts can contain information for different cities. For example, Shanghai and Guangzhou for the top chart and Beijing and Fuzhou for the bottom chart. Is there a way to construct the filter in order to create that option?
Here you go:
1. Right-click on the dimension and create the group as shown below:
2. Select the required values and click on Group and give an alias as required. You can repeat this till all the values are part of a group. Or check the "Include 'Other'" for the remaining values.
3. You can now use this group dimension as required.
Hope this helps.