Thanks for posting to the forums.
To help look after you and to solve your problem. Can you please provide a sample workbook of what you are trying to do?
As Chale mentions - a sample would help a lot - otherwise we can only give generic advice.
For now here is the generic advice -
If you need to use information across data sources (i.e. the people in 1, company in the other) then you're either going to need to create a relationship between the 2 data sources
or use a custom parameter with calculated fields
Its certainly possible in Tableau