How to create merged dimension using WebI REST SDK?

Hi Team,

I need to create multi universe based WebI report using REST SDK.

For that I know, I need to create multiple queries in data provider, which I am able to do.

But to show objects from both the queries in single report block ,I have to first merge two dimensions and use that merged dimension into application block.

So I want to know ,how to merge two dimensions using WebI REST SDK and use that into a report block?

Please help.

Regards

Amit