AFAIK the answer is no. You will need to examine the source owners account and extract the manager's email and then insert it into the transfer command. Obviously if the manager's email field isn't populated then you're on your own.
I can think of ways to script something like this, but it's still a multi-step process.
1. find the users whose drives you want to transfer
2. extract the manager's email (if it exists) to a csv file with two columns: primarEmail and manager_email.
3. use the previous csv to feed the gam transfer command.
If you're using advanced gam here are some suggested readings:
Maj Marshall E Giguere
NH Wing Director of IT
Civil Air Patrol, U.S. Air Force Auxiliary
GoCivilAirPatrol.com
nhwg.cap.gov

Volunteers serving America's communities, saving lives, and shaping futures.