Here is how you can handle this using sub-rooms. 

Say, you have a room called Main Floor and your age groups are as give below with the teacher-child ratios:

• Age 1 year to 2 years — 1 to 6 
• Age 2 years to 3 years — 1 to 8 
• Age 3 years to 4 years — 1 to 12
• Age 4 years to 5 years — 1 to 17
• Age 5 years to 6 years — 1 to 20
• Age 6 years to 12 years — 1 to 23

We recommend that you create the following rooms in iCare:

• Main Floor 1
• Main Floor 2
• Main Floor 3
• Main Floor 4
• Main Floor 5
• Main Floor 6

And, register the children in these sub-rooms. In reports, if you type Main Floor, all the sub-rooms will get included. Or, in Advanced Filter you can use wildcard matching by typing Main Floor%.