Trying to add users to group. one user already created own orgnization so now I cannot add

Trying to add users to group. one user already created own orgnization so now I cannot add

I have a user who created her own organization and now I am unable to add her to my organization. How do I fix this. She created a spreadsheet and I am unable to share this with anyone else. I tried adding her to my organization but since she has her own I cannot add her. She shows in a group of mine, but there is no way to make the sheet she shared with me sharable. I am completely confused.