Mash bananas and peaches. Add cherries and lemon juice, mix well. Stir pectin into fruit. Cook on high heat until fruit comes to a rolling boil. Immediately add sugar, stirring until mixture comes to a rolling boil again, stirring constantly, boil for 1 minute. Remove from heat, skim foam with a metal spoon for 5 minutes, to cool slightly and prevent fruit from floating. Immediately ladle into hot sterilized jars, filling to 1/2 inch from top. Seal.