I think the answer is probably going to be no but you never know so I’ll ask anyway.
In the same company we have two distinct business units that both use projects but in the same way. Lets call them business unit A and business unit B. Both business units have different sets of engineers assigned to them. Business unit A wants to prohibit engineers from business unit B from booking time to projects belonging to business unit A.. We thought about using project access on but that casts too wide a net and would impact common support groups like purchasing and finance that support both business units which would make the access groups painful to continually maintain. We were hoping at the time entry level there was an easy way to make projects (or sub projects, or activities for that matter) invisible to those engineers that shouldn’t be able to book time to them..