Enum List with User Input in Second Column

I have an ENUMLIST with base as Reference Table Name, Which is having List of Product with Column Header as Item Name and QTY. Now The list is populating with Item Name where I can select multiple Items at once but I need QTY column along with Item Name Column so that user can input the no. of qty in that column which should be added to single cell by comma separated value. Kindly advice me how to overcome this issue.