Is it possible to exclude the REST API of Business Central from being authenticated in BRMS or BPMS 6 ?

Issue

• Is it possible to exclude the REST API (/business-central/rest) of Business Central from being authenticated in BPMS 6 ?
• Is there any setting in BRMS 6 for unprotecting its REST URL from the back end Siteminder based authentication for a REST call , so that users can exclude the particular URL not to be authorized and stay unprotected for access?