Third party authorization server

Hi, i have a case i’d like to solve with Tyk
or at least know if i have a chance

I wish for an application to use tyk gateway without using client credentials to access another application,
but giving an existing Oauth2 token.
I can’t use Tyk built in Authorization server, because it doesn’t support the token exchange feature.
Therefore i need an external Authorization server
Edit : even if Tyk’s embedded Authorization server were to support the token exchange, it would not work because the token to exchange is coming from another Authorization server

Here is a example of what i wish :

I saw the identity broker feature, but i’m not sure that’s what i wish.
Do i have a chance, or should i find another way to solve my issue ?

I read Tyk gateway / Tyk Idenitity Broker conenction to Oauth2
but i didn’t found a hard yes answer

Thanks of for any help