The main idea of an archive is to contain all the items on it. Even that, if you want to have two different pages with different projects/galleries on them, you can follow this.
- Create two categories for projects.
- Assign projects to those categories.
- Create two different pages and set for both of them Custom Home Page template and select Portfolio Category. On each one, you have to set one category.
That’s how you can achieve two “different archives”.
The steps presented are described for projects but you can follow the same steps for galleries too.