gistfile1.txt

connections {

    swan {
        pools = students
        remote {
            id = %any
            auth = eap-radius
        }
        include swanctl_swan.conf
    }

    swan-itsadmin {
        pools = itsadmin
        remote {
            id = %any
            auth = eap-radius
            groups = swan-itsadmin
        }
        include swanctl_swan.conf
    }
}

...this ends up in connection "swan"...
09[CFG]   candidate "swan", match: 20/1/1052 (me/other/ike)
09[CFG] peer config match local: 20 (ID_FQDN -> XXY)
09[CFG] peer config match remote: 1 (ID_RFC822_ADDR -> YYY)
09[CFG] ike config match: 1052 (XXX.XXX.255.64 YYY.YYY.YYY.YYY IKEv2)
09[CFG]   candidate "swan-itsadmin", match: 20/1/1052 (me/other/ike)
09[CFG] selected peer config 'swan'
09[CFG] RADIUS server 'localvpn' is candidate: 210
09[CFG] sending RADIUS Access-Request to server 'localvpn'
...
05[IKE] received RADIUS attribute Filter-Id: 'swan-itsadmin'
05[IKE] RADIUS authentication of 'XXX.XXX.XXX' successful
05[IKE] EAP method EAP_MSCHAPV2 succeeded, MSK established
05[ENC] generating IKE_AUTH response 3 [ EAP/SUCC ]

connections {

    swan {
        pools = students
        remote {
            id = %any
            auth = eap-radius
            group = kickout
        }
        include swanctl_swan.conf
    }

    swan-itsadmin {
        pools = itsadmin
        remote {
            id = %any
            auth = eap-radius
            groups = swan-itsadmin
        }
        include swanctl_swan.conf
    }
}

15[IKE] received RADIUS attribute Filter-Id: 'swan-itsadmin'
15[IKE] RADIUS authentication of 'XXX@XXX.XXX' successful
15[IKE] EAP method EAP_MSCHAPV2 succeeded, MSK established
15[ENC] generating IKE_AUTH response 3 [ EAP/SUCC ]
15[NET] sending packet: from XXX.XXX.255.64[4500] to YYY.YYY.YYY.YYY[4500] (80 bytes)
09[NET] received packet: from YYY.YYY.YYY.YYY[4500] to XXX.XXX.255.64[4500] (112 bytes)
09[ENC] parsed IKE_AUTH request 4 [ AUTH ]
09[IKE] authentication of 'XXX@XXX.XXX' with EAP successful
09[CFG] constraint check failed: group membership to 'swan-itsadmin' required
09[CFG] selected peer config 'swan-itsadmin' inacceptable: non-matching authentication done

I know this file is being read, as it is using the nas_identifier from it:

/etc/strongswan/strongswan.d/charon/eap-radius.conf:
eap-radius {
    load = yes
    accounting = yes
    accounting_close_on_timeout = yes
    accounting_interval = 600
    accounting_requires_vip = yes
    close_all_on_timeout = no
    # Use filter_id attribute as group membership information.
    filter_id = yes
    # NAS-Identifier to include in RADIUS messages.
    nas_identifier = VPNB
    sockets = 32
}
    
...plus a server { }