This is not possible. VIA supports the following authentication schemes. If you want an extra check, your best bet is to use IKEv1 and use a certificate and then username/password.
IKEv1 (two-phase authentication method)
- Phase 1 - PSK or X.509 certificate
- Phase 2 - XAUTH (username/password)
IKEv2 (single phase authentication method)
- X.509 certificate
- EAP-TLS
- EAP-PEAP (username/password)