$ sudo -u user2 env | grep PATH
PATH=/specialPATH/bin

$ sudo -l
...

secure_path=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin,
    (user2) NOPASSWD: /usr/bin/env
    Defaults>user2 secure_path=/specialPATH/bin
...

$ sudo -g group2 env | grep PATH
**PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin**

$ sudo -l
...
    secure_path=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin,
    (user1 : group2) NOPASSWD: /usr/bin/env
    **Defaults>%group2 secure_path=/specialPATH/bin**
...

$ sudo -V
Sudo version 1.8.10p3
...

@stretch$ sudo -V
Sudo version 1.8.19p1
...