How to kill or slay certain process

Hi All
I have this question if somebody could help me please?

in booting QNX i have many drivers installed like that

devc-8250ser -p/dev/uart1
devc-8250ser -p/dev/uart2
devc-8250ser -p/dev/uart3
devc-8250ser -p/dev/uart4

of course as it is known in end of my program I can kill all those processes using

slay -f devc-8250ser , but this will kill all four up.

my question how can I kill or slay one of the processes up like say
only dev/uart1 , but keep the rest running.

Thanks All

something like:

pidin -p devc-ser8250 ar | awk ‘//dev/ser1/ {print $1}’ | xargs kill