Slice peaches and remove all pits. Set aside one peach with pieces cut into wedges.
In a blender, combine sliced-up peaches, half the bottle of rosé wine, St-Germain Elderflower Liqueur, and fresh lemon juice and blend until smooth.
Transfer the mixture to a pitcher, and add in the remaining half of the bottle of rosé wine.
Place one peach slice in the bottom of each of the 8 popsicle molds.
Fill each mold to the halfway point with the mixture, and then place a second peach slice.
Top off each mold with remaining mixture, and fill almost to the top, leaving a little bit of room for the popsicles to expand when they freeze.
Freeze overnight and then serve!