Can fortiauthenticator itself act as a radius accounting proxy source?

We need the fac to works as a 802.1x server for hundreds of switchs,and then forward the radius accouting messages to dozens of the-third-party firewalls for SSO.

The fac can proxy the radius accouting messages  from swithes to destinations.However it's to complicated to create hundreds switches as proxy sources,and it's nearly impossible to set these source to dozens destionations.

Can fac itself act as a radius accounting proxy source like windows NPS?

I failed to config interface ip of fac or 127.0.0.1/localhost as the source ip.