There is the possibility to limit bandwidth using a protocol, know that there is a possibility to limit bandwidth via IP Networks> QoS> User Groups, more if you want to limit the bandwidth per protocol is possible?
Would Application Prioritisation be what you are looking for? We could prioritise one protocol above the other to ensure it is served first at high load.
But do share more of what you have in mind with us - there might be something interesting that we could explore further.