separating access for procurement documents within the same business unit

we have two separate procurement teams:
-External Procurement team who is handling the direct materials procurement operations.
-Internal Procurement team who is handling the services, consumables, and expenses procurement operations.
We have one legal entity in Saudi Arabia with one business unit where both teams are serving.

The key requirement is that buyers from Internal Procurement team will be able to access and have full authority on any purchasing document/data related to any buyer in the internal procurement team, but they cannot view any documents/data related to any buyer in the external procurement team and vice versa.

We need to check the applicability of this requirement considering that we have only one business unit.