Multiple Select List and Advanced display options

Multiple Select List and Advanced display options

I'm using a Lookup field in FormA with Field Type: "Import Data" from FormB and Display Type: "Multiple Select List" (one-to-many relationship), also using the Advanced display options (displayformat showing 3 fields from FormB)

1. In the FromA EDIT mode, I want to display the records in the Multiple Select List that are only the related to FormA. Is there a way to do this? currently it display all the records in FormB with selected iteams related to FormA.

2. As a work around, I tried to clear the Multiple Select List in On Edit On Load, and add the FormB records manually based on fetch criteria, but now it display blank records (I mean, the displayformat is not showing)