I believe that you will need to use regular expressions to create a pattern that matches the one in the SBV files. Based on what I've found on the official website about TextWrangler, I don't think it supports this function. Additionally, the developers recommend a new tool for text editing. It's called BBEdit, but just like in the previous case, I couldn't find that feature as well, which means it doesn't have support for.
If you have the possibility, download CODA and install one of its plugins called RegEX. You can use it to match the lines. On the page, switch to plugins tab and type regex. You can then use Google to see how RegEX is working and how you can match it against your files.