Parents with 2 or more toddler kids, how do you discourage jealousy among your children?

I will always tell my elder boy that didi 'buy' the toys for him or didi help to bring the balloon back for him. And he is so happy that he always goes to the didi and say 'I love u lei' sayang and kiss the little one. at times he will take didi toys or teether to play so I also will tell him, next time when didi grow up u also need to share ur toys n books with didi...