Any decimal number presented to Venus-type device /VRM should be alarm-able via a threshold.
VRM allows the tracking and graphing of decimal numbers sent to it from various devices attached to a Venus-type device. An example might be a Ruuvi sensor sending temperature or humidity data for storage and graphing.
At the current time, there is no way to set an alarm either on the Venus-type device or VRM for the Ruuvi (or other) devices not specifically called allowed by Victron Firmwares.