Variable within a variable

Content

I'm trying to build a report with rather large amounts of merge text in the fields and so using variables for some of it (type=replacement value). What I could really do with though is the ability to use a variable within my variable, and RN doesn't seem to allow me to do that, I just get a vague error. Has anyone found a workaround for this?

If I type in all the logic I need, I run out of space in the box!