You can create as many groups of trackers. as you want based on the plan that your company is enrolled.
Adding trackers to a group
The main characteristic of the groups is that the trackers can be share among them, being the same tracker in two or more groups at the same time. This fact allows you to create groups with different purposes: aggregating different vehicle types and obtain a particular visualization for each one, create specific notifications for a vehicle selection of your fleet or simply structure your fleet information.
Adding POIs to a group
Add POIs to a existent group allows you to create a notification rules related with a POI (as can be the proximity to a given position) and apply it to a group of trackers being the rule linked to both group and POI.