[CentOS] Starting a process at a specified nice value.

I wonder if someone could point me to the appropriate docs for my question? If 
I would like to cause my system to always start 'smbd' processes at priority 
7 for example, how would I go about doing that. 

I'm assuming there's a better way than running a cronjob every minute to 
renice existing processes. 

I'd appreciate some help pointing me in the right direction.

Thanks.