Stir together honey and ¾ cup water in a large container. Add grapefruit juice, and stir well; cover and chill about 1 hour.

For each serving, place ice in a Mason jar, filling 2/3 full. Add ¼ cup rum, and fill jar with grapefruit juice mixture. Pour drink into a shaker, and add 1 sprig rosemary and 1 slice jalapeño pepper; cover and shake 10 seconds. Pour mixed drink back into jar; add more ice, if desired.