Rails (3.2) asset pipeline - is it possible to have a condition for the current entry point into the pipeline?

Question

I have several applications for resource pipelines using shared resources. I need these resources to be configured according to which application required them, for example, to have a built-in asset or not.

For instance:

application.rb

config.assets.precompile +=  %w( app1.js app1.css )
config.assets.precompile +=  %w( app2.js app2.css )

app1.js

 *= require blabla1
 *= require common

app2.js

 *= require blabla2
 *= require common

I want to have different results in accordance with the current entry point into the pipeline, for example, something in the spirit of the following:

common.js.erb

var src="<%= currentAssetPiplineEntryPoint == 'app1' ? image_path('img.png') : asset_data_uri('img.png')%>"

doable?
If not, is it due to bad practice?

thank