Relate to other records within same table

We have a table for training materials.  I need to be able to have a record in the table and have it associated to other "related" records within the same table. 

I.E. We may have a record that is video training and have another record that is written user guides but both are on the same topic.  We would like to connect the records as "related training" so the user can view an embedded table of all the associated training material. 

I have created a relationship where the table is joined to itself and there is the embedded table, but I cannot figure out how to select multiple records to add as related training. 

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Stephanie Meyer
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