I assume you want to load all the files in a single package. You can create 'on success' or 'on completion' workflows between each transformation task. They would point from the SQL Server connection icon to each text file connection icon. Edit each workflow and choose the source step.
If it makes it visually easier, you can copy the SQL Server connection icon by right-clicking and choosing 'copy', then right-clicking in a blank area and choosing paste.
Hope this helps.
Greg