is it possible to alter the config_uri submitted to all the `p*` commands before it is read/parsed?

[Jonathan Vanasco]

I've recently changed the design of a project, and would prefer to specify the directory a config_uri is in, instead of the file itself -- then append "config.ini" to it in code.  

is this possible?  it doesn't seem possible with the way plaster is designed, but i wanted to ask.