Pass connection string to execute process task SSIS

I need to pass an argument to process task and it's a connection string and value should be picked from one of the connections in Connecti开发者_JS百科on Managers. How do I do this?

Thanks!

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i would store the connection strings in a table and use Parent Child configurations with property expressions

if you a variable in a package then you will need to modify it manually, not so good