In a small saucepan, combine 1 cup of sugar and 1 cup of water. Bring to boil, then reduce to a simmer until sugar is dissolved. Remove from heat. Let mixture cool and then store it in the refrigerator.

Combine the mixers, bourbon, 1/2 cup of the simple syrup and bitters. Chill for several hours or up to 24 hours.

When time for serving, pour into a punch bowl and add seltzer. Garnish with citrus fruit slices and mint leaves.