setting specific appearance frequency of the target stimulus

Hi everyone!

I was wondering if it is possible to show stimuli setting a specific frequency of appearance; 
For example, I was thinking on building an experiment in which there are various distractor stimuli and one target stimulus, and I would like to manipulate the frequency of the target stimuli; 
specifically, I would like to show target every 3 times is shown the distractor stimuli; and then every 5 times; 
Furthermore, I was wondering if it is possibile to randomize these sequences of "every 3" and "every 5" etc...

Thanks in advance for your help and support