Yen,
First, I admire your commitment to stepping up your bike fitness, you inspire me a whole lot. Second, I'll only suggest that your goals and intent for the group rides, if you continue to have them, is to clearly communicate your intent and purpose for your rides. If everyone knows what you are seeking they are more likely to cooperate with you. If you do/did this, my apologies, I just want to see you be able to use every tool we bicyclist have to achieve your goals. Best of luck in achieving your goal.

Bill