Suppose you want the Bouchard's row before the other rows. You can modify the transformation as follows:
From the Flow category of steps, drag an Append Streams step to the canvas. Rearrange the steps and hops so the transformation looks like this:
Edit the Append streams step and select as the Head hop the one belonging to the Bouchard's rows, and as the Tail hop the other. Doing this, you indicate toPDI how it has to order the streams.
Do a preview on the Add sequence step. You should see this:
You changed the transformation to give priority to Bouchard's issues.
You made it by using the Append Streams step. By telling that the head hop was the one coming from the Bouchard's file, you got the expected order—first the rows with the tasks assigned to Bouchard, sorted by progress descending, and then the rows with the tasks assigned to other programmers, also sorted by progress descending.