If you have multiple leads in the same campaign belonging to the same company, Smartlead offers the feature to stop messaging other people within a company once a person replies from that company.
To enable the feature, click on the Gear Icon on the top-right when editing your campaign, then scroll down under General tab and find 'Company Level Auto-Pause'
Note: The following domains will be ignored: gmail.com, outlook.com, yahoo.com, aol.com, icloud.com, zoho.com, protonmail.com, yandex.com
**Note: Only applies on the first upload of the lead list.