I'm curious about your backend - do you have private peering links with these providers? Isn't streaming to multiple providers really bandwidth intensive for you?
Exactly, you can choose one of our servers which is closer to you can then configure your streaming software/encoder with the ingest URL & key provided.
You can configure the platforms which you would like to stream to from Castr's dashboard. You can enable and disable the platforms on the fly as well.
Good luck with your venture!