Avoid supply planning of items planned by replenishment plan

We have a requirement where, within the same organization, certain items need to be planned using a Replenishment Plan, while the remaining items should be planned using a Supply Plan. Although there are separate item attributes available to define different planning methods, I came across documentation stating that the Supply Plan can also plan items whose planning method is set to Replenishment Planning.

Based on this, I have the following questions:

1. In which scenarios does the Supply Plan consider items that have the planning method set to Replenishment Planning?
2. Since the organization is the same, how can we prevent Supply Planning from planning items that are intended to be planned only through the Replenishment Plan? I am unsure whether using a simulation set would be effective here, given that the number of items could be very large.