Cut the grapefruit into quarters or eighths, and cut the limes into quarters (reserving the additional wedges). Juice the limes and grapefruit pieces into a pitcher with ice, then add the spent fruit into the pitcher
Stir your non-alcoholic sangria with a long wooden spoon until well mixed (you’ll want a chance for the agave nectar to blend in with the other liquids, and let the fruit swish around to infuse flavor into everything).