Add new connection to existing universe foundation

Hi,

I have universe which was converted to UNX, I retrieve the universe to add to my projects, The data foundation is already created when i retreie the universe to local projects, which displaying all the tables (universes structure) The universe has more then 100 table and derived tables. I wanted to add one more connection to this data foundation to add few more tables from different database, but I don't see that options. Is possible or does IDT has the feature to add new connections to the existing universe, Is there any option available where i can avoid the starting from the scratch,  

thanks

kareem