the practitioners at the playgroup are there to support your child and you. Do they know how you feel? It will be in their policy that bullying is unacceptable and will not be tolerated (ignoring is a way of bullying). That goes for the children and for the parents who use the setting.
We once had an issue with a young parent who heard racist comments about her, every day, while she waited to collect her son. The supervisor tried hard to sort it out, and most of the parents were sorry when they knew it was upsetting the young woman. She ended up making some new friends and they joined the committee together.
They should at least let you pick up your children a little earlier, if you don't want to stand with the others.