Hide Group email from global address list

Your best bet for accomplishing this en-masse is to export the groups via PS and put the ones you want to hide into a CSV or txt file with the ID or name, or Identity property.  Then use get-content or import-csv and use set-unifiedgroup -HiddenFromAddressListsEnabled  $true property for them all at once.

Here's a CMDLET I use to do the export for my tenant.  (more info than you need, but it's nice to have a complete report, as well as see all of the attributes you can manage)

Get-UnifiedGroup -resultsize unlimited | select DisplayName,Name,Identity,Id,AccessType,ManagedBy,RecipientType,RecipientTypeDetails,MailTip,GroupMemberCount,GroupExternalMemberCount,PrimarySmtpAddress,ModerationEnabled,HiddenFromAddressListsEnabled,IsMailboxConfigured,ManagedByDetails,Notes,SharePointSiteUrl,SharePointDocumentsUrl,SharePointNotebookUrl,WelcomeMessageEnabled,AutoSubscribeNewMembers,AlwaysSubscribeMembersToCalendarEvents,CalendarMemberReadOnly,CalendarUrl,HiddenGroupMembershipEnabled,InboxUrl,Classification,GroupPersonification,YammerEmailAddress,AllowAddGuests,WhenSoftDeleted,SendModerationNotifications,ModeratedBy,GroupType,IsDirSynced,AcceptMessagesOnlyFrom,AcceptMessagesOnlyFromDLMembers,AcceptMessagesOnlyFromSendersOrMembers,AdministrativeUnits,Alias,GrantSendOnBehalfTo,PoliciesIncluded,PoliciesExcluded,EmailAddressPolicyEnabled,IsExternalResourcesPublished,ProvisioningOption,ConnectorsEnabled,IsMembershipDynamic | export-csv .\O365GroupsReport.csv -NoTypeInformation