SSIS Packages Dynamic Connections

1) We are doing data migration from SQL Server 2000 OLTP design to SQL Server 2005 OLAP design.

2) We have used SSIS packages and data flow tasks in which we mentioned connection strings for source and target
containers.

3) We have a master execute package which contains series of execute packages in relational order.

4) When we execute this master package, we should be able to dynamically specify different source and connection
strings for all packages.

5) Can we do it with dtexec option /Conn[ection] IDOrName;ConnectionString
We know what to give for ID or Name but what do we give for ConnectionString. Will it be the source/target one? Can we specify both source and target ones with which the data flow packages get executed.