I think, it has nothing to do with card games, but you could have given us a little bit more info.
It seems, they are on a seminar or workshop, where they are learning how to make sense of "brainstorming", how to make order of chaos, and being introduced to the idea of clustering.
That's where the cards come into it.
See the website below:

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Note added at 1 hr 28 mins (2005-02-11 20:13:15 GMT)
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After the \"brainstorm\", they have a large number of cards, all with ideas, and they put them on a wall for everybody to see, or lay them out on a table. The cards are all there to be seen and to choose from, not like a card game. We are talking about the ideas on the cards. The object is to see, which are the most important ones, and reject the ones which are the least important. What they are doing now, having all these ideas, is to put them into order.
Then they start a process, where the first round is to collect those cards, which have the clearest ideas on them.
They put them up in a group. Often they stick them on a board on the wall, so it is easy to see them.
The second round will be to choose the card they are most confident about. They get them up as well, in a separate cluster.
So that\'s the \"getting the second round of cards up\".
Physically it can be just a pile of cards on the table. It is a process of selecting and grouping the cards.




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Note added at 1 hr 32 mins (2005-02-11 20:17:24 GMT)
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Looking at your points, they select the \"related ideas\" cards first,
then the put the remaining cards up, or lay them out, and start the second round of selection. It doesn\'t say, what is the second objective of selection exactly, but it may be said somewhere else.