One primary key in two tables
The two options would be:


Model them in the same table with a property to distinguish their type (such fields are often called a discriminator) and all the properties of both types.
Model them with a third table holding their common properties (and usually a discriminator also) and one child table per type. This pattern is referred to as table inheritance.


The latter option would be preferable, but I'm not sure how one would implement it in Access (I've not used that in a decade and a half).