Let root execute the scripts, but the start/stop commands contained within the scripts would be executed under sudo.
So, let's say you've got process.sh, which you want to run under svcacct. Execute process.sh as root, and its start command would be:
/usr/bin/sudo -u svcacct /path/to/startCommand.sh
And you'll see that the process is running under the authority of svcacct. No password required.