Why does for loop return only the first entry from my lists?

Why does for loop return only the first entry from my lists?  Stripped down script as follows.

groups=(baremetal production staging)
baremetal=(test1 test2)
production=(test3)
staging=()

for group in ${groups[@]}
  do
        echo $group

    for host in ${!group}   # only adds the 1st
      do
           echo $host

      done
  done


./test.sh
baremetal
test1
production
test3
staging