Given the size of the project (based on the disk consumption you listed) I would say most methods that might be used for splitting the project are high risk. I think the least risky option is for you to make a full copy of the project for the Commercial group, and then begin deleting the non-Commercial data from that copy.
Any method of selectively copying data using the API or by directly manipulating the database is high-risk, in my opinion, because you may not correctly maintain relationships between different entities.
How much of the data in the project is just for the Commercial group? If it is only a small amount, it may not be such a high risk to try to selectively copy data.
If you want to try to selectively copy data from one project to another, your options are:
- do it by directly accessing the databases
- do it by using the OTA API to select the data, and then post it into a new project
- do it by opening the source project and in another window a new, empty project, and then through the UIs select items to copy from the source and paste them into the empty project.
Given the size of the project, you may also want to look into the Purge Results functionality and see if there is any data that you can get rid of.