How to create a custome role to be associated to a specific BU?

Summary:

Create a custom role associated to BU.

Content (required):

Requirement is to make a Custom Role for each BU so they don't have to use "Manage data access for users" to assign the BU.

Now if we assign a user with a role example "Cost Accountant" oracle gives automatic access to the BU associated to that Employee (A) (HCM)

But when that user requires access to BU (B) i will need to go "Manage Data access for users" and assign to BU (B)

Can this step be skipped if i give a custom role which is associated to a BU to the user?