Drain grapefruit and cherries, reserving juices.
Bring reserved juices and sherry to a boil in a medium saucepan. Remove from heat; add gelatin, and stir 2 minutes or until gelatin dissolves.
Chill 30 minutes or until consistency of unbeaten egg white; stir in grapefruit, cherries, and pecans. Pour into a 6 1/2-cup mold. Cover and chill 8 hours or until firm. Unmold onto a serving dish.
*1 1/2 grapefruits, sectioned, and 1 1/3 cups fresh grapefruit juice (about 3 grapefruits) may be substituted.