Partial use of foreign key attributes

Quite some time ago I asked this in a similar form already. But as it always hinders me in design and implementation (and, in getting 0 differences when synchronising data dictionary with model), I like to discuss/request it again.

In my logical model, there is in an entity b having some foreign key attributes coming from a relationship between entity a and entity b. Let's say entity b has 5 fk attributes from entity a. I only need 2 of them as primary key attributes (together with some more attributes of the entity b).

In this example, I can set the 2 FK attributes as PK attributes and save the design, but as soon as I reopen it, all 5 foreign key attributes are automatically checked as PK attributes again. As entity b has relationships to other entities (entity c, d, ...), it has quite a lot of unwanted impact, i. e. creating unwanted foreign key attributes in these other entities.

And, of course, if I engineer the logical model to the relational model, the unwanted attributes are transferred to unwanted columns.

My request is to allow for exactly the PK attributes I need , independently of being it a FK attribute or another attribute. That would help a lot.

Thanks and regards,

Robert