@bd528 Try this (replace the static data with your SP List). The collection colCompleteGroupFinal will have the desired result.
ClearCollect(colCompleteGroup,
GroupBy(
Table({Product:"AAA", Part:"111", Complete:"Yes"},
{Product:"AAA", Part:"222", Complete:"No"},
{Product:"AAA", Part:"333", Complete:"Yes"},
{Product:"BBB", Part:"444", Complete:"Yes"},
{Product:"BBB", Part:"555", Complete:"Yes"},
{Product:"BBB", Part:"777", Complete:"Yes"},
{Product:"CCC", Part:"888", Complete:"No"},
{Product:"CCC", Part:"999", Complete:"No"}),
"Product",
"Complete",
"CompleteGroup"
)
);
ClearCollect(colCompleteGroupFinal, colCompleteGroup);
ForAll(colCompleteGroup As _colCompleteGroup,
If(CountRows(Filter(colCompleteGroup, Product=_colCompleteGroup.Product))>1,
RemoveIf(colCompleteGroupFinal, Product=_colCompleteGroup.Product && Complete="Yes")
)
)