Just be careful to let your new wards come to you. Be there for them when they are ready. Be consistent and reliable. Remember, don't try to win them over, and certainly don't try to buy their love with gifts. They need the essence of you, and in time you will become an important person in their lives.
Children have no built-in limit to the amount of people they can love.
As a stepgrandparent, you extend the child's intergenerational support system, and everyone benefits as a result. Effective stepgrandparenting is an art, but it can be a source of revelation, great joy and wonder for those who undertake this role with sensitivity, tenderness and compassion.