So I did this previously if the ACC adopted the 3-5-5 here is how I would do it.
Clemson- Georgia Tech, Florida State, NC State
Duke- North Carolina, Virginia, Georgia Tech
North Carolina- Duke, Virginia, NC State
NC State- Clemson, North Carolina, Wake Forest
Florida State- Clemson, Miami, Louisville
Georgia Tech- Duke, Clemson, Virginia Tech
Virginia- Duke, North Carolina, Virginia Tech
Virginia Tech- Virginia, Georgia Tech, Miami
Boston College- Syracuse, Pittsburgh, Wake Forest
Wake Forest- NC State, Louisville, Boston College
Syracuse- Pittsburgh, Boston College, Louisville
Pittsburgh-Syracuse, Boston College, Miami
Miami- Florida State, Virginia Tech, Pittsburgh
Louisville- Florida State, Wake Forest, Syracuse
I did it the best I could to protect every team's history. I as an SU would have loved Miami as our 3rd but Pitt has been playing them in the Coastal so we would get Louisville as our 3rd and its an easier matchup anyway.
Every team plays those 3 teams every year and then rotates 5 of the other 10 every year. Top 2 teams play for the conference title. Use basketball tiebreakers if there is a tie for conference title game.