Inter-project dependencies

I'm doing some Delphi (2010) work this summer, and I've stumbled upon this problem:

My project consists of reusable backend library and a bunch of GUIs that tap into its interface. In this circumstances I've decided to make the backend and GUIs separate projects within single project group (I hope my train of thought is correct). The problem is, how can I include units from the backend in a GUI project?

I've tried to modify Project Options > Directories and Conditionals开发者_开发百科 but compiler still complains about being unable to find proper .dcu's.

Any ideas? Your help will be appreciated.

In D2010, the Directories and Conditionals in the project option refers to (and is specific for?) the resource compiler.

I guess what you are looking for is the Project Options->Delphi Compiler->Search Path

Search where the compiler is generating the DCU files. (2)
In project options you must add the source directory on you have de PAS files (1) or the directory where compiler generate de DCU files.
(1) In the "Search path" edit.
(2) This directory is the "Unit Output Directory" edit.

Regards