One-to-many version of a reference set selector

Hi All!   I am aware that the reference set selector is used for many-to-many association between 2 entities. However, I wish to select customers into one group only, meaning each customer belongs to one group and one group can contain more than one customer. I wish to do it via creating a new group, then selecting the customers that belong to that group. So far, I can only achieve this with a reference set selector but I cannot implement a many-to-many association between the customer and the group entity.   How do I create something like a reference set selector, but for a one-to-many association only?
1 answers

In the Group_NewEdit create a Add-button that opens a popup with a dataview of that group. Include in that dataview a datagrid showing all Customers with Xpath “not(Customer_Group/Group) “, which only shows the Customers that are not yet connected to a group. Make the datagrid multiselect and add a button that assigns Group to each of the selected Customers and then closes the popup.