InfoPath Dev

I have a similar but a little more involved scenario that I think the above formula might help solve, but I'm at a loss as to how to modify it due to lack of full understanding of how substring-before and substring-after work - especially in the above formula.   I'm thinking that if one character can be replaced with a string of ...

Ok, I'm a newbie to Infopath, but think I know enough to be dangerous. I've searched through the forum for my particular issue, but could not find anything like what I need to fix. I'd appreciate any help you can provide. I have a form that has a drop down list box tied to a secondary data connection (XML resource file) with three ...