After Effects Position Expression Help

Hey everybody, I am wondering if anyone in the forum has experience with messing around with expressions in After Effects. I needed to find a way to create self-resizing lower thirds so I looked up some tutorials on youtube that could help me. I managed to get the main header to work the way I wanted it. The problem is that I have to place a caption underneath the header (for example, HEADER: Chris Richards, Caption: Vice President). This composition is meant to be used as a template that can be edited in Adobe Premiere, so whenever someone would type a new name in, I would want the caption to be right aligned (flush right) under the name in the text box. My dilemma is that I don't know how to scribe an expression that would move the captions position in accordance with the finishing of the header. if anybody can help me out, I would greatly appreciate it. Attached are some images of the project file.