In IOM version 2.0 you can create virtual fields which can copy data values from other columns. For example, if your file has columns A-L, the first virtual field will be column M. You can define M to be a copy of the data in another column, such as column E. This way you can “copy” the address columns that are mapped to the constituent address into virtual fields and map them as the relationship addresses. Attached are some screenshots of a sample data file along with screenshots of the field mapping and virtual field mapping - assuming your data is similar to mine, it should do what you need. Also see pages 39-41 of the v2.0 user guide for more information on using virtual fields.
If you have further questions, please let us know. Also feel free to attend our office hours on Tuesday afternoons where we can take a closer look at your files.