Path organization

[quote pid="393232" dateline="1642922824"]
"One system has only one controller?"

[/quote]
No, they will not use the same controller, but, in a most of time, they will use same functions and requests (model database).
And they will also use the same page template.

I not wanna make the same function to a both of systems.

It is a best practice to make the same function to each system?
Is there a possibility to avoid a redundancy in this case?