How are you assigning the waves? Is there a dropdown on the Tours table like wave 1,2,3 and when you make a tour? If so then you could just go to the table-to-table relationship and create a summary field on the Parent side. Think default option is a Total of related records, then just make 3 more summary fields that do the same thing but add a filter that says if Tour - Wave = 1, then repeat for each wave.
For importing you could import no problem. you just need to make sure you have a column called Related Presentation or whatever the field thats in the tours table that was created from the relationship. Then just put the ID of the presentation in that field for the various tours you have.
Hope that helps.
