halacha - L'Hafrish Challah with Dough Made by Multiple Women?

I am wondering if small portions of dough, made by separate women in a challah baking class (thus each small portion would be owned by a single woman), can be combined to create the requisite amount of dough to require blessing and separating? For example, if 10 women make individual doughs from 1/2 pounds flour, combine their doughs so that the combined dough has at least 5 pounds of flour, then bless and separate challah from the combined dough? If so, can the dough then be separated again for each woman to take her dough home to bake? This is very common at challah baking classes, and I am wondering if blessings can be said in class. Thank you so much!