It's ultimately your decision, however, I see many benefits of collaborating with your staff and having everyone conduct the top band.

As an assistant in the middle of my career, I was given many opportunities to lead the Wind Ensemble. The HD at the time would have me consistently work fundamentals with the Wind Ensemble. Now, to be completely honest, at first I thought, "why can't you do this yourself?" But as I look back I'm thankful for the opportunity that was given to me to help establish my band sound with the "top" band. What worked, I took with me the next period... What didn't, I didn't try again OR was able to workshop with the HDs guidance. Because he didn't just let me run through and jump off the podium. I remember I tried that once because I thought I had other things I needed to do and he put me right back up there and expected me do it right. He had expectations for what he wanted out of me and the students. This also gave me more ownership into the program as a whole. The fundamentals then led to conducting repertoire.

This was my experience and it helped me to develop as an educator. It also showed me what true mentorship was. Maybe think of this as an opportunity to not just grow your ensemble but develop your staff as well. You might actually learn something yourself too(I KNOW, SCARY right?).

I think it's important for all of our students to see all of our faces, regardless of the size of the program. Not all of the kids are into ME so if they have an opportunity to work with B or C then that has lifted that kiddos spirits for that part of rehearsal. If we develop our students AND our staff then they may not be so quick to "seek that HD job" themselves (as mentioned in one of the responses) and then you have depth in your staff as well as your students. Or if they do move on, wow, what an opportunity and skillset you gave them to be successful. We even force our student teachers to work with the top band and perform a piece on the Spring Concert. Their product from beginning to concert....good, bad, and ALL the ugly. The band staff rehearses 0% of that piece. Sure it takes trust but it's worth it for the music education of everyone in the room. It also puts the responsibility on all the staff and not just you.

I'm rambling at this point. There's a lot more I could say on this but I think I've made my point.

I say give it a chance. If it makes you uncomfortable then you're probably learning something about yourself, your staff, or your students!