How can we improve WHMCS?

By default, a customer will receive only one copy of the mailing containing merge data for the first matching product found in their account. However, ticking a check box will mean an email is sent for each item that matches the given criteria and therefore a single client may receive the email multiple times - once for each qualifying product they have. Unfortunately, the checkbox option is on products/service email type only.

When Sending Emails campaigns, I expect to see check boxes for all email types i.e Products/service, Addon, Domain and General Email Types, where I can tick to email each item that matches the given criteria and therefore a single client may receive the email multiple times - once for each qualifying product they have.

See attached image for the checkbox I am referring to.