@Christina654
First..... it will depend on whether you plan to recieve different group bookings for each room separately or only 1 guest group at a time and allow access to certain rooms depending on guest group size. The latter option is a bit more complicated and difficult to manage thru ABB.
If you have room A, B, and C and you want to be able to have 3 separate guest groups in each room you need to have a separate listing for each room. And then to attract larger groups who want to use all 3 rooms you would need to create another listing that includes all 3 rooms together and then link the calendars.
https://www.airbnb.com/help/article/1864/how-do-i-link-airbnb-calendars-for-multiple-listings
https://community.withairbnb.com/t5/Help/Linking-Calendars/m-p/590813?advanced=false&collapse_discus...
https://community.withairbnb.com/t5/Hosting/NEW-Linking-Airbnb-calendars-to-each-other/m-p/407748?co...
Hope this helps~