You can add as many rooms or groups as you wish! The ages must lead from one to another. For example:
Baby Room: 3 months - 12 months
Toddler Room: 12 months - 24 months
Pre-school: 24 months - 60 months
You can stipulate how many children each group has capacity for and the typical ratio. This will formulate the parameters for your current and forecasted Occupancy.