9.2.2 "Why GNU su does not support the wheel group"

This is the famous phrase at the bottom of the old info su page by Richard M. Stallman. Not to worry: the current su in Debian uses PAM, so that one can restrict the ability to use su to any group using pam_wheel.so in /etc/pam.d/su. The following will set the adm group in a Debian system as an equivalent of the BSD wheel group and allow su without a password for its members.

     # anti-RMS configuration in /etc/pam.d/su
     auth       required   pam_wheel.so group=adm
     
     # Wheel members to be able to su without a password
     auth       sufficient pam_wheel.so trust group=adm