On timesheets and expense reports you can address a project in another company and post to these projects. If you consume items, this is not possible. It should be possible to do intercompany item consumption. E.g. you go to your own stock and get a part to be build into a prototype product. The project is owned by another company, so the item consumption should be posted on the project in the other legal entity. You should also be able to do purchase requisitions and item requirements related to a project owned by another company.