Yes, you can have entries for multiple groups in an ACL – that's actually the whole point of the ACL feature.
(Except you don't need to have the groups "own" the folder in any way. Aside from disk quotas, the "main" group doesn't receive any special privileges that an owner would, so you could instead pretend the opposite, that the "group ownership" is just a limited 1-entry ACL.)
So in setfacl
terms, your ACL would look like:
g:ftp_read:r, g:ftp_read_write:rw, g:ftp_read_write_execute:rwx
Though it doesn't look like a very useful set of permissions to me. Over FTP, users cannot execute arbitrary files anyway, no matter the permissions. Meanwhile, they require the execute permissions on directories – having just +r access on a directory merely allows you to see the filenames.
This seems more useful:
g:ftp_read:rx, g:ftp_read_write:rwx
You can set this as the default ACL for a directory and the POSIX ACL system will automatically "mask" +x on newly created files, resulting in +r for files but +rx for directories.
The "mount options" thing hopefully went away in 2014 or so. In recent kernel releases, ext4 enables ACL support by default. – user1686 – 2016-05-11T05:05:27.070