You would most likely configure Mangocam to access your IP cameras directly, not via Blue Iris.
Both for recording simultaneously (local recording with higher bandwidth / frame rate / retention) and cloud recording (lower bandwidth stream) for added security and convenience.
However, there is a profile for Blue Iris on Mangocam, just forward the RTSP port and configure your channel id.
Any further questions please send directly to support at mangocam dot com.