How to merge the datatable in dataset? Asp.net C#

Question

i have one excel document and multiple sheets.sheets have many columns and row.i upload the document into my project.and the multiple sheets is bind to tables(sheet name is set as table name) using for loop.after the bind i change the table name to source1,source2,source3 (three sheets). Now how to bind(merge) the three tables in single table (source1).

 

 

I have Tried:

 

i have tried to rename the all tables to same name but the duplicate table is not allowed.how to bind the same table.