The native class joins or associations within a report definition do not appear to directly support this. However, you can create a calculated field that extracts the common values from the columns you want to establish a match on and then use those calculated fields to join together. The benefit also is that you can index those columns for improved performance. If you used a Connect SQL rule instead with a 'like' join it usually does not perform as efficiently since it would not be optimized for your join.