Changing Template on Dynamic Calls

Hello everybody,

I am building a website for a magazine/conference company and have some advanced requirements for the posts which display a conference website.

Now even though this is a little more complicated eventually, I’ll try to put it simple right here.
Each conference has the same layout, however there is a different header picture for each conference. I wonder whether I can exclude that header picture from the actual content of the post but rather, give the post a tag, that corresponds to a picture number in the media library, and then call that number (of the picture) dynamically in the theme.

For example:
The user clicks on conference 36. The content is tagged with 36 and there is a loop in the theme that reacts to ‘is_tag’ and then (and this is the tricky part) recognises the tag number and pulls the corresponding picture from the database.
I suppose that the number of the tag has to be replace with some php code (a variable) that can be reinsterted when calling the picture so that I would end up with something like (excuse my bad php understanding) “<?php if is_tag(<?php conferencenumber ?>)” <img src=”<?php echo get_option(‘home’); ?>/wp-content/uploads/topbanner<?php conferencenumber ?>”.

Please let me know if I’m getting too far ahead or if this is somewhere conceivable.

Thanks so much.