anu_1555,
Thank you for your clarification. So in your case, I suggest you change the logic a little bit and create one chart with multiple series instead of multiple charts. Then, position them correctly by using multiple
yAxes and you can use the exporting module with default options. Please, check the simple demo below - it can need some customization by you, but it shows the main idea.
Demo: https://jsfiddle.net/BlackLabel/8n4p3mve/
Let me know if that fits your requirement.
Regards!