Ask HN: Can VPN/SSO integration be used to auto-login to SSO enabled sites

At my company I have to log into our VPN each day to be able to access our internal tools/sites. Our VPN is already SSO enabled, or at least it triggers our SSO provider's 2FA. It seems like once I'm logged into VPN, when another site that requires SSO Auth redirects me to the SSO Provider to have me authenticate, that the SSO Provider should be able to determine that I already signed into VPN, and from there for just automatically authenticate without me needing to fill in the log in form. I think it's technically feasible, but I'm guessing it isn't implemented.