They met when Ms Roesler was tutoring Ms Paterson's child, and together created a local group that linked with the national autism organisation.
"We got talking and decided we needed a group," Ms Paterson said.
"It's been amazing, the actual need has been quite phenomenal; we've been quite overwhelmed by it."
Ms Paterson has been a volunteer for many years and a field officer for more than a year.
There are 55 Wairarapa families as members of the organisation, "but a lot more that aren't" and still access the services.
Autism New Zealand recently unveiled a new logo, including a prominent 'A' combined with the familiar jigsaw puzzle component, symbolic of the challenge autistic children have in piecing together how they see the world.
Autism New Zealand now covers what are called "autism spectrum disorders" including more mild conditions such as aspergers syndrome.
Ms Paterson has set up a "one stop shop" for parents to access information and advocacy to help themselves and their children.
"People need to be supported," she said.
"It's a journey and there are quite a few battles involved."
Siblings of an autistic child can get forgotten also, and relationships can break up.
Ms Paterson started her role voluntarily, but realised the need and number of people affected were "much bigger than we thought".
Ms Roesler has come on board to provide information and support to schools to help them understand children with autism. The pair are both part-time and "rely solely on the generosity of grants and charity".
"We need to have funding to keep our positions but we need more hours," Ms Paterson said.
Discovering their child had autism was a difficult experience for both women, and that memory motivates them to be there for others.
Her reaction was "grief - there was no support" Ms Roesler said.
"There was no support; you just got 'Congratulations, your son's autistic,' and sent out the door."
From that time there is a battle, both in helping the child grow as best they can, and working with the education system.
"You never stop battling; you achieve one milestone and there's another around the corner." Ms Roesler said. "It would very tiring without support I think."
In Wairarapa, the two Wendys will continue to be there providing support and information to those families affected by autism.