u/pinkshirted

I planted two different varieties of pawpaw tree and one of them is flowering for the first time! It looks like the other one will be blooming as well, but I don’t think the blooms are going to overlap in time ( even though when I bought them they said the varieties were good to pollinate each other). Is it possible to freeze or refrigerate the blossoms or pollen from the first one and use it to pollinate the other one? If so, do you have any tips on how to do this?Thank you.