Signature Workflow to look inside document contents for conditional rules

We are developing a signature workflow in SharePoint 2010, and need to look inside the .docx document to apply conditions for where the .docx document is routed for signature.

For example:

• if the document says "XYZ" for a certain field in the .docx file, we'd route to Mr. "W"
• if the document says "ABC" for a certain field in the .docx file, we'd route to Mr. "D"

I'm assuming we're breaking into the full Visual Studio development (and out of the SharePoint Designer realm) since we'll have to look inside the contents of the document for the workflow to work from.

Any examples would be appreciated!