Once receiving new messages from Telegram groups, the list of groups to which the bot is added will be refilled. In the integration settings, you can leave useless groups as a bot and no longer receive these messages.
Visit Admin Center >> Apps and Integrations >> Channel app >> Telegramer >> Accounts >> Click on your account and switch to the "Groups" tab.
Here you will see all groups to which your bot has been added. You can leave any group and no messages from this group will reach your Zendesk.