Watermelon Lime Spritzer

2 cups seedless watermelon, cut into cubes
1/2 cup ice cubes
2 cups lemon-lime flavored soda, divided
1 lime, cut into wedges

Place the watermelon and the ice cubes in a blender and blend until smooth. Add more ice cubes for a more slushy mixture. Slowly add 1/2 of the lemon-lime soda and blend until smooth. Pour into glasses, garnish with lime and serve.