How do we share one table in two data set and create report using two data set

Hi

I have two questions..

1st  ............

How do we Create one report using two data set (both dataset are from one database), is there any method to do that?

2 nd ..........

Because My dataset size is huge, I used import method it takes normally long time to refresh , so I am going to split that dataset into small data set  and publish into same BI service. my issue is some tables are common in both data set ( ex Company Table), so How do we share one table in other dataset without creating same table in each data set.

Thank you.

Harsha