If you make a schematic symbol and add it to the sheet. Then right click on the part and refactor -> convert part to ports, you can explode a part to a sheet.
Then you have a sheet that is represented as the 3 schematic and BOM parts, but one sheet symbol in the high levels. Also look into repeat statements.
I have a USB port and associated circuits on one sheet and use Repeat(U,1,12) to put 12 channels of them in a schematic. You can have group ports or separate ports. Then in the PCB, you have rooms for each. Route one room and then select Design -> Rooms -> Copy Room Formats. Click on the routed one first. Then click on each of the other rooms and it will auto place and route. Very handy for doing a job once with multi channel designs.