The answer to that is yes, there is nothing that would preclude me from doing that as a supervisor. The issue is that, at the end of the day, for the vast majority of funding for CIHR investigators, you have a fixed amount of funding. If you increase to the students, there is less towards the research that needs to be done in the lab as well. It's a very precarious balance.
The direct answer to your question is that there is nothing that would preclude that.