Conditional formatting for every 12th entry

[shadedlight]

Is it possible to create a conditional formatting for every 12th occurrence that has a fill color and says the word yes in column c? The occurs of every 12 won't be in order. So the conditional format will reference the name and if it's the 12th occurrence

 

[eibi]

paste in c2:

=IF(MOD(COUNTIF($A$2:A2,A2),12)=0,"yes","")​

and drag to fill.

Then, conditional formatting formula will look like this:

=c2="yes"​

See attached.

 

[Hui]

Remove the old CF

Select A2:C61
Goto CF
Apply a new CF
Use a Formula
=MOD(COUNTIF($A$2:$A2,$A2),12)=0
select a format
apply

If Column C can also be No or Blank
use:
=And(MOD(COUNTIF($A$2:$A2,$A2),12)=0,$C2="Yes")