Not really. You'd just have to take advantage of the social organization already in place.

First, you can organize circles within clan/sept, and interactions between DFs from different clans/septs would have to go through a Shadow organization within one or more of the Societies (eg: the Maidens). It would mean Melindrah knew the DF within her sept, perhaps a few from her clan, and those among the Maidens. The risk of exposure is minimal, considering the DF among Aiel would be believers in the Shadow but there wasn't much DF among Aiel would be asked to do. Until recently, that is.

What would bind all this together would be the Shadow's leaders among the culture, a small group of Wise Ones, who pick candidates they can convert to the Shadow as their apprentices, secretely prepare them to face what they'll see in Rhuidean and so on. WO are the ones who transcend the barriers of clans and societies and can go anywhere... they'd be the ones who know all the DFs. Someone like Bair would have the extra advantage of being able to pass orders and gather information by visiting DF Aiel in their dreams. She'd make an excellent "Head of DF Aiel", close to the circle of the top WO too.

One thing that could be suspicious about Bair is that she arrived to Arad Doman very late, which Aviendha noticed. If she's a DF, it's possible she was ordered to join the Aiel in Arad Doman and get back near Rand. Of course as a Dreamer she could have contacted Amys and co. and asked them to come fetch her.

People have suspected Sorilea a lot, but people forget Bair was at her side in all those suspicious scenes. I think Sanderson turned Sorilea into a red herring, attracting attention on her to distract us from Bair.

I find it extremely suspicious Bair decided on her own to go to Rhuidean and waited to ask Aviendha directly for a gateway, without debating this with the other leading WO first. To me it's as if she wanted to be sure she'd be the one to go, as if she feared if she brought it up the others would decide Amys or Sorilea was a better choice, or that they should all go. Bair will be in the position to have the "final word" about the vision.

I also found it a little suspicious she obviously recognized the name Nakomi as something from the far past, but didn't tell Aviendha what it was. I suspect Bair wanted Aviendha not to know who Nakomi was (I still believe it's a fair possibility Nakomi is an ancient deity, ie: a female name for the Creator used by the Da'shain very long ago, only remembered by the WO. I believe the Green Man or the Gardener was a male equivalent. The AS/channelers who learned to channel and developped a new cosmology with The Wheel, the Pattern have established the more generic term Creator, displacing the older concepts, linked to Nakomi and the Green Man, the Great Serpent, the Dream etc. Nakomi is in real life the name of a mother goddess among Amerindians. She could alternatively be Cyndane, as the Amerindian Nakomi is linked to Dreams. The "vision" could be a cruel revenge of Cyndane on Aviendha. She could also have done this on order from Moridin. He vowed revenge for the Bowl of Winds. He said that if he failed to stop them, those who disrupted his careful planning and delicate ploys would be tracked down and they'd live to pay.... It's apparently not empty threats... Moridin sent Shiaine to Andor, gave her Carridin who had failed, Moghedien's two BA who had failed to stop Elayne/Nynaeve, he forced Careane to kill Adeleas and thus reveal there was a BA infiltrated in Elayne's small group... he got her to take risk after risk.. assassinating Kinswomen, and seemingly Merrile and Talaan as well. Moridin was cruel... he made sure Elayne would have a hard struggle to gain Andor, and it wouldn't come without civil war and chaos, but he planned for her to get the throne in the end. She barely had time to savour her victory that he destroyed the capital of her realm. This attack was long in planning, apparently its timing long decided. I suspect Moridin didn't plan for Elayne to escape with her life, she did because of Merrilor, and that couldn't be late, the attack had to go forward. The assassins sent to the palace were probably meant for her too. This is a fairly elaborate revenge, but Moridin could tell himself this wasn't a waste as it also would work perfectly to cause Rand great "pain of heart" - a reminder of the deaths of Ilyena and the children, and beside it's the opening blow of the LB. Destroying all Aviendha's hopes for the future might be a similar type of elaborate revenge. If I'm right, Nynaeve is better watch her back, as Moridin must hate her all the more than she participated in both the BOW affair but aggravated her "faults" by pairing with Rand to Cleanse saidin.).