In principle, this is not possible.
Only one authentication service (IdP) can be registered with the Teachme Series.
Note
Technically, it is possible to configure multiple IdPs to be linked on the IdP side, but we cannot guarantee operation in such cases.
If you proceed, please conduct sufficient testing beforehand.
If you temporarily need a Group for operational testing, please contact our support desk (support@teachme.jp).
Related: Which services (IdPs) can be integrated with Single Sign-On (SSO)?
https://help.series.teachme.jp/hc/en-us/articles/63062070990617