We have carried out detailed analysis of transient events, which were discovered by Gaia and published by ESA Gaia, DPAC and the Photometric Science Alerts Team (http://gsaweb.ast.cam.ac.uk/alerts). Among them, we detected many objects with the similar features in their lightcurves presented at Gaia alerts webpage. Special attention was given to CV candidates and blue hostless transients. Using the available data, we could identify some different groups of objects. We performed successful follow-up observations for one of such objects, namely Gaia17cuh, based on our prediction of its activity and revealed the subsequent outburst. Now we develop a data processing tool which will allow one to predict further outburst activity for about one hundred objects in the Northern hemisphere including determination of their amplitude and periodicity. This new so-called alerting subsystem should help for a faster classification of Gaia transients.