Hi Dirk,
So I guess you want to avoid typing the same attribute for every shortcode.
Yes in that case you can use “custom fields” shortcode parameter.
Shortcode parameters
Insert a custom field named “postid” with value “33” in your page.
Now use $$custom_field:postid$$
in your shortcode content. When you insert this shortcode in the post, this parameter will be replaced by 33 which is taken from the page’s custom field.
Thanks,
Aakash