CSS changes for changing bulk pages (grouping pages)

i need some help with a few things.

the goal is to find a way of changing the CSS codes of multiple pages so that all the current pages are applied with the same changes + but also any future pages can be easily added to this group so that the changes will be applied in to them too.

1) is there a way to classify pages into categories so that they can be easily added to those groups? from the wp-admin / page edit area?)

2) using those groups can we define some CSS changes that will apply only to them?

3)CSS changes
- changes to do - http://monosnap.com/image/fCrn2pvDDASHs7X4KvGb2hjkm4Euio

1) Title needs to be smaller approx 1/5th
2) Title needs to be in lowercase
3) A margin added between the Title and Photograph.
4) add another margin between photograph and main text
5) change the "back to members" link on the bottom right from <h3> to <h5>

here is a link of the one of the member's page - http://tinyurl.com/pc7u7tj
here is the main page containing all the pages - http://tinyurl.com/qff2ahp

Support access is open