admin access in bitbucket project

[adas1]

We have 16 repositories for one project in Bitbucket, and we have also added a group named project name: XXXXXX" and it's have read access. But I want to grant admin access to one user in that project. I can open one repository at a time and then grant access, but any other method is to grant only project admin access to one user, without opening them one by one.
Note-Project named group have only Read access.