Hope you are well,
Depending on what type of fields you want to combine depends on if it is possible or not. Would it be possible for you to provides some additional information regarding what you are trying to do then I will be able to provide a solution for you.
I also wanted to provide you with a link to Wiki the explains the use of Advanced Sub Query Functionality
This basically allows a user to query more than one view (and sometimes data source) at the same time and combine the results in a single report.
I hope this helps.