The dynamic support in SSIS never really impressed me, but you need to consider the type of user it was geared towards, non-developers.
Take a look at this post, it should help you get started with this:
SSIS Dynamic Connections[
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In the past, I've also wrote C# scripts that do similar manipulation, but I wasn't really impressed with that route either. Here is a YouTube video that demos it:
Introduction to C# Scripting in SSIS[
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If you are using SQL Server 2012 and higher, I would suggest taking a look at this:
SSIS 2012 Projects: Deployment Configurations and Monitoring[
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If your packages are identical or generic enough, you might be able to make of environments.