you need to create a new linking table that will create the many to many relationship between the Ranges and Hansdsets, then use the Data Assist Manage Relational Table behavior to create the records in the new linking table.
handsetRangeID - Primary Key Column
handsetRangehandsetID - relates the the Handsets.handset_ID column
handsetRangePSRangeID - relates the the PSRange.PSRange_ID column
Andrew Read posted the following thread a while back with a good explanation of using the data assist Manage relational table behavior: