Apache Logs don't show which mapped domain was hit

I feel like I asked this once before, and got an answer, but I can’t find it back for the life of me…

We have lots of mapped sites on a network, and our Apache httpd logs just show:

/about

without what domain was requested. Is there a way to have our Apache logs show which mapped domain was requested here? Whether it was site1.com/about or site2.com/about?

Thanks!