Don't have your exact requirement mapped out but I've seen something similar so maybe this helps you get closer.

At the bottom of a report this type of view was added so it showed all serial or lot references for each item on the order. So not in a line underneath just it's own discreet section. Here is the code if it helps out to try this instead.
Globals:
ItemTrackingAppendix Report Item Tracking Appendix (6521)
TrackingSpecCount Integer
TrackingSpecBuffer Record 336
ShowTotal Boolean
ShowCorrectionLines Boolean
ShowGroup Boolean
TotalQty Decimal
OldRefNo Code[20]
OldNo Code[20]
ShowLotSN Boolean
DataItem ItemTrackingLine as an Integer
PageLoop - OnPreDataItem()
// Item Tracking:
IF ShowLotSN THEN BEGIN
TrackingSpecCount := 0;
OldRefNo := 0;
ShowGroup := FALSE;
END;
ItemTrackingLine - OnPreDataItem()
IF TrackingSpecCount = 0 THEN
CurrReport.BREAK;
CurrReport.NEWPAGE;
SETRANGE(Number,1,TrackingSpecCount);
TrackingSpecBuffer.SETCURRENTKEY("Source ID","Source Type","Source Subtype","Source Batch Name",
"Source Prod. Order Line","Source Ref. No.");
ItemTrackingLine - OnAfterGetRecord()
IF Number = 1 THEN
TrackingSpecBuffer.FINDSET
ELSE
TrackingSpecBuffer.NEXT;
IF NOT ShowCorrectionLines AND TrackingSpecBuffer.Correction THEN
CurrReport.SKIP;
IF TrackingSpecBuffer.Correction THEN
TrackingSpecBuffer."Quantity (Base)" := -TrackingSpecBuffer."Quantity (Base)";
ShowTotal := FALSE;
IF ItemTrackingAppendix.IsStartNewGroup(TrackingSpecBuffer) THEN
ShowTotal := TRUE;
ShowGroup := FALSE;
IF (TrackingSpecBuffer."Source Ref. No." <> OldRefNo) OR
(TrackingSpecBuffer."Item No." <> OldNo)
THEN BEGIN
OldRefNo := TrackingSpecBuffer."Source Ref. No.";
OldNo := TrackingSpecBuffer."Item No.";
TotalQty := 0;
END ELSE
ShowGroup := TRUE;
TotalQty += TrackingSpecBuffer."Quantity (Base)";