My team is using this policy to create unique CN

What this policy does is queries ALL objects in AD and the compares each
object to the CN created. we have about 10k users in AD. AD team is
extremely sensitive about this.

what they want us to do is filter based on first character of the CN

eg :
James Smith - jsmith
Jayne Smith - jasmith
Jayne Smith - jaysmith

Is there a way to do this by just getting only users starting with J in

Thanks for the help