Enable the ability to deliver campaigns at different times OR days of week within Mixpanel

E.g. I want to send a weekly ad hoc email, 50% on Wednesday/50% on Thursday.

OR

I want to send 50% at 7am and 50% at 5pm. 

In my previous roles, we would have to use statistical sampling. Does anyone know how to do this within Mixpanel or can Mixpanel please implement the function.

Thanks!