Using a Swiss teams type of event in ASE Scorer Version 9 you can conduct a round robin event.
In the session definition click the [Teams draw] button (alt-T) and define your own draw.
On subsequent rounds using [session][new], choose [no] to "automatic draw' and the same draw option is available on each round.
Care is needed with an odd number of teams where you want to play a 3-way match. The 3-way is over two rounds/sessions and so in the second round of the two, the teams in the 3-way should not be included in the number of teams and the draw for that round. If you have an odd number of teams (after eliminating those in the 3-way,e.g. a team drops out) then a bye must be played for that round only.
When doing a manual draw for 3-way matches over two rounds you must specify a different number of teams in the draw on each round.
For example with 7 teams to start, the draw is:
7 - 4
6 - 5
1-2-3 (over two rounds)
Because it is over two rounds the next round for 1,2,3 is already defined.
Then for the next round add a session but with 4 teams not 7
and use draw
4 - 6
5 - 7
and next (7 teams)
2 - 6
3 - 7
1-4-5 (over two rounds)
and next (4 teams)
7 - 2
6 - 3
and next (7 teams)
2 - 4
3 - 5
1-6-7 (over two rounds)
and last (4 teams)
5 - 2
4 - 3