We also wanted to do this. Instead of using the "components" field, we have set up separate requirement items for each of our systems and their components. We then use associations to create an appropriate relationship between each "business" requirement and its corresponding "system" requirement(s).
What is nice about this is we can now do traceability in either direction. We can start with a business requirement and see the related systems and their components. Or, we can start with a system or component and see all related business requirements that are driving the use of that system.
The reason we have set up requirements for systems and their components instead of using the "components" field is because the "components" field just doesn't offer the same level of functionality as a requirements artifact. It can't be nested. It can't have descriptions and comments, etc.