One BP Picker for several BP Line Item Picker

Hello Everyone,

I have a BP1 (Line Item BP Type) which have 5 line items.

I have a BP2 (Simple BP Type), that I need to link to 10 line items records of my BP1 (2 line items records for each line items ==> 2x5=10).

I thought I could create a BP Picker and then create 10 BP Line Item Picker on my BP2. But with reference process functionnality on uDesigner, I need to have a BP Picker for each BP Line Item Picker (I thought I could use the same BP Picker for each BP Line Item Picker). So, I need to add 10 BP Picker on my BP2 but it's impossible because the users will not fill the 10 BP Picker.