If we compromise on the format a little and sometimes only send 2 teams to a venue, then it can be done in 6 rounds.
Site 1 Site 2 Byes
(4 2 3) (6 7 5) [1 8 -]
(3 8 -) (1 2 5) [4 6 7]
(3 7 1) (5 8 4) [6 2 -]
(4 1 7) (2 6 -) [5 8 3]
(3 5 -) (1 6 8) [7 2 4]
(8 2 7) (4 6 3) [1 5 -]
So above team 3 has 1 bye while the other teams have 2 byes each. There are also two repeated games in the schedule, so:
In round 4 the match up between teams 1 & 7 does not need to be played.
In round 6 the match up between teams 3 & 4 does not need to be played.