The setfacl command can be used to control file access for groups as well.
setfacl -m d:g:ftpw:rwx /srv/ftp/
setfacl -m g:ftpw:rwx /srv/ftp/
setfacl -m d:g:ftpro:rx /srv/ftp/
setfacl -m g:ftpro:rx /srv/ftp/
Here note two commands for each group. The first sets the default which will be inherited may new subdirctories in the future. The directory itself needs its own acl.
I'm on my tablet, in a restaurant, so I can't provide vsftpd options I can't look up. I'll leave it to you to read the vsftod.conf man page for other options. Maybe tuned to the operations in your first post.