is there some way (natively) to 'mark' some tasks (Meeting, Email, Task, Call, Search task, Notes and Post) as "internal" in way to filter it on the 'Business Process' and then do not send email alert to customer or should we create a custom field (is-Internal: Ture/False) for that purpose and also edit the FORM for these activities described?

Just to explain, let's say that our tech team should schedule internally a meeting to discuss about that case or even register some call to another partner or engaged external person.