You could use Tables/Summary with a self-made grouping column:
Names Default to here();
PickFile();
dt = Current Data Table() ;
dt << New Column( "bins",
Numeric,
"Continuous",
Format( "Best", 12 ),
Formula( Floor( :x / 2 ) + Floor( :y / 2 ) * 1000 ),
Set Selected
);
dt << Summary(
Group( :myBins ),
Min( :x ),
Min( :y ),
Sum( :"Sum : [16O]"n ),
Sum( :"Sum : [12C14N]"n ),
Sum( :"Sum : [12C15N]"n ),
Sum( :"Sum : [31P]"n ),
Sum( :"Sum : [77Se]"n ),
Sum( :"Sum : [80Se]"n ),
Sum( :"Sum : [82Se]"n ),
Sum( :"Sum : [-]"n )
)