Place the pomegranate juice, orange or grapefruit juice and 1/2 cup raspberries in a small pot. Set over medium, to medium-high heat, bring to a simmer, and simmer about 6 to 8 minutes, until reduced to 2 cups.
Remove the pot from the heat. Set a fine sieve over a bowl. Strain the pomegranate mixture through the sieve, pressing on the raspberries to get out all of their juice.
Taste the pomegranate mixture and, if desired, sweeten with honey. Now cool the pomegranate mixture to room temperature, transfer to a jug, cover and refrigerate until well-chilled, at least three hours.
For each drink, pour 1/2 ounce of orange liqueur into a fluted glass or wine glass. Set a few raspberries and 2, half and thin slices of orange or grapefruit in the glass. Now add 1/2 cup of the pomegranate mixture. Top up with 1/2 cup or so of sparkling wine, and serve.
Options: To make these drinks non-alcoholic, replace the wine with soda water or non-alcoholic sparkling cider.