Hello anersantana,
I've done this many times. Please use the below listed configuration and let me know how it goes.
Configuration for restricting access to a particular windows group on AD
group-policy noaccess internal
group-policy noaccess attributes
vpn-simultaneous-logins 0
address-pools none
ldap attribute-map LDAP-MAP
map-name memberOf IETF-Radius-Class
map-value memberOf <DN of the VPN group> <Group Policy Name>
aaa-server LDAP-AD protocol ldap
aaa-server LDAP-AD host <IP-of-Windows-AD>
server-port 389
ldap-base-dn <AD base DN>
ldap-scope subtree
ldap-naming-attribute sAMAccountName
ldap-login-dn <login user DN>
ldap-login-password <password for login user DN>
server-type microsoft
ldap-attribute-map LDAP-MAP
group-policy <Group Policy Name> internal
group-policy <Group Policy Name> attributes
vpn-simultaneous-logins 3
vpn-tunnel-protocol IPSec l2tp-ipsec ...
address-pools value <Address Pool Name>
.....
.....
tunnel-group <Tunnel group name> type remote-access
tunnel-group <Tunnel group name> general-attributes
authentication-server-group LDAP-AD
default-group-policy noaccess
Regards,
Jatin Katyal
** Do rate helpful posts **
~Jatin