Adjoin
You stand with another woman and, with your fingers, adjoin yourselves together. You are united, you are one.
Look around you. Other women are adjoining their fingers and standing with you. There's hundreds, no, thousands of you standing together.
せつ
つ
None
All of the women who are now adjoining together are in sets (せつ). Sets of two, of course. One woman with another woman, standing in unison.
Picture a bunch of women protesting together. They're holding hands in sets, adjoined together.