Generating Random Names and Comparing to Existing List.

I am in the process of generating random names using =Rand(), grouping into 4 using =rank() and filtering. Using that group of 4 I create 2 teams of 2 which creates a random pairing doubles match. I then do this for several games and matches. My problem occurs due to keeping a track of who has played with each other before.

For example week 1 Player A & Player B and Player C & D. The following week Player A & Player D vs Player C & B this is an example using only 4 players but we have upto 20 members could potentially come and play. Also not everyone comes every week.

Any ideas of how I could ensure the players weren't partnered (exist in the list) with previous pairings but keeping it random. As I have generated it several times but it always has gaps of partners who have played before.

I have attached an example workbook to this post.

Players - List of players assigned a random number and rank. If attending Y if not N.
Matches - Rank from previous pages split into 4 groups according to number.
PairingsAndResults - Pairings with a tick (using checkboxes) have already been paired (TRUE) and blank checkbox (FALSE) doesn't exist. Names are concatenated below to show pairings as text. (would prefer not to have the table at the bottom but unsure how to code without)
Games - Displays the matches. For this example there are 20 players, playing 4 matches. If players not played before = names if they have played before = blank

Thanks, J