loading two similar Rails Engine in single app

Hi all,

I trying to load two similar Rails Engine in single app
..

In my app Engine A like a core and engine B like a specific to some
other purpose.
In this two engines have many models,some models have shared in both
engines.

In this i faced one problem if i shared the model means all the method
is not loaded correctly..
.Ex,i have article model in both engines Engine A have 5 methods and i
have over-ride the model in Engine B it has 2 function.
what i thought is Engine B article model have Engine A and Engine B
methods
,but what it's happen article model have only Engine B model methods
only.

if i load manually means it working correctly.
I have load one engine in one single app it is working correctly..
Please tell me how to load 2 similar engines in one single app...

in Gem file i have loaded the engine ->>>

gem 'core-engine', :path => 'Engines/core-engine'
gem 'microsite', :path => 'Engines/microsite'

Thanks.