App with customizable playoffs?

We are trying to find an app that will let us set up our playoffs schedule the way we want it. I’ve tried ESPN, YAHOO, and SLEEPER, no luck. Unless somebody knows a way to do it that we are missing.

12 team league.

What we want :
Regular season goes week 1-11. (play every team once)

Top 2 seeds get A BYE in the 1 week long “Wild Card Round” (week 12)

WC Round: week 12 ONLY. 3v6. 4v5. (1,2 have a BYE)

Round 2: weeks 13, 14.

Championship: 15, 16.

This seems to us to be the most fair. But we haven’t found a way to set it up. Any help would be AWESOME.