Data drilling of a bar chart into a line graph with multiple metrics

[phleung90]

Hi all 

Now I have an idea in building the chart and with the data drilling function. However, I am struggling to visualize it. 

The main idea: I have a bar chart which contains the conversion rate of web user to final subscription, which break down by different countries like as follows 

What we want to do is to add a data drilling, that when we click into the bar chart, there is another shows the follows:

• The no.of new visitors with time development 
• The no.of converted customer  with time development 

Like this,

but couple of changes: 

Change the conversion rate to absolute number, and 2 lines at the same graph

Example: For our premium product in London, we click into it, and would like to see how much new users and how much of them are converted in each week

Is there any way that I can achieve it? Thanks!