> For the complete documentation index, see [llms.txt](https://docs.bird.com/connectivity-platform/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bird.com/connectivity-platform/contacts/managing-group-subscribers.md).
# Managing group subscribers
If you want to automate certain actions, like opt in / opt out responses, you can easily do this with Flow Builder; you can learn how to set this specific flow [here](https://support.messagebird.com/hc/en-us/articles/360000358457-How-to-set-up-opt-in-opt-out-automatic-SMS-subscriptions).
**Opt out**
When sending out a campaign, make sure your contacts are in a group.
If you configure a rule like the one shown below, those users who reply ‘Stop’ will be automatically removed from the group specified:
\
This will remove the contacts from the group, but they will remain in your address book.
**Opt in**
You can also create multiple flows for one Number, allowing you to trigger different actions depending on pre-specified keywords within the response of the user.
A company could use this to keep track of customers who are interested in a certain offer. For example: if you send ‘Reply SPA to enter our prize draw’, and want to keep all the replies for this offer in one place, you can set up something like this:\
\
\
The relevant replies would be automatically forwarded to a phone, email or added to a group, or you could even configure an automatic response.
There is no limit to how many contacts can send you to opt in or opt out responses
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