Combine the sugar and 3 cups water in medium saucepan set over high heat. Bring to a boil and cook until the sugar is dissolved. Add the tea bags and steep for 5 minutes. Remove the bags, return the mixture to the heat and cook until reduced by half. Transfer the mixture to a container with a lid, and refrigerate until cold, at least 1 hour.
Combine the cooled hibiscus syrup, grapefruit juice, tequila and lime juice in a pitcher. Add the limes, oranges and raspberries, and then cover and refrigerate for at least 1 hour to allow flavors to meld.
Fill tall glasses with ice and add about 1/2 cup of the mixture to each. Then fill to the top with the cold club soda and serve.