I think it's a bad idea to make any ordinary user a member of the root group.
You might be able to use ACLs to solve your problem. Because the directory is owned by root, run the below command as root
setfacl -m u:jim24:rwx /var/www/vhosts/example1.com/httpdocs
It's a modification on commands I used in http://www.linuxquestions.org/questi...-group-730046/
to allow apache to write somewhere in a user's home directory. If you get errors like "operation not permitted", check post #3 in the above thread.
You might need to install some SW to support ACL. E.g. Ubuntu 10.04 does not seem to support it out-of-the-box while 12.04 does.
If ACLs are too much work to get going, I would change the group of the directory /var/www/vhosts/example1.com/httpdocs
from root to something like www-users (and create that group as well) and make jim24 a member of that. Change the permissions on that directory to 775 in that case.