Adding 3rd party root CA certs in CertSrv cacerts

Hello,

I spent a decent amount of time searching but could not find an answer to my question. 

Is there a way to add 3rd party certs in the CA certs response CertSrv provides in https://<hostname>/certsrv/certcarc.asp ? 

If this needs to be redirected to another forum please let me know. 

Thank you, 
PK