In a small saucepan, stir cornstarch into milk until dissolved.
Mix in 1/2 cup honey and molasses.
Bring to a boil, stirring constantly. (Mixture will separate when cooking but will be smooth when done.) Remove from heat.
Gradually add grapefruit juice, stirring.
Return to heat and bring to a boil again, stirring constantly.
Remove from heat and mix in grapefruit sections.
Cool mixture slightly and spoon into pie shell.
Preheat oven to 375° F.
In a small bowl, beat egg whites until foamy.
Gradually add 2 teaspoons honey and lemon juice, continuing to beat until stiff peaks form.
Spread meringue over pie, touching all edges of the crust.
Bake on top shelf of oven until golden brown.
Cool slightly, and then chill in refrigerator until firm.
If desired, decorate with orange and grapefruit sections.