You could use this schedule where the 4 rows are the rounds and 4 columns are the 4 different games.
(H A) (F C) (E D) (G B)
(F D) (H B) (G A) (E C)
(E B) (G D) (H C) (F A)
(G C) (E A) (F B) (H D)
If you make A,B,C and D the seeded teams, then they will not play each other in any first round match. Hope that helps.