This can be done using a search filter in the LDAP Configuration tab. Add the memberOf attribute to your search filter in the LDAP configuration tab to allow members of only specific groups to sign in.
For example,
If you have to allow users of only one group use:(&(objectClass=*)(mail=?)(memberof=<distinguished name of the group here>))If you have to allow users of multiple groups use:
(&(objectClass=*)(mail=?)(|(memberof=<distinguished name of the first group>)(memberof=<distinguished name of the second group>)))
