Declaring variable inside another one or inside a script / SQL Execute task

Hey Gurus, 

I want to have the following user variables:

a) DB Connection - DB Names
Type: String
Scope: package

b) Business Process - Finance or sales
Type: String
Scope: package

c) Stored Procedure - If @Business Process = 'Finance' then EXEC USP_Name1 else EXEC USP_Name2
Type: String
Scope: package

d) Destination - If @Business Process = 'Finance' then Location1 else Location2
Type: String
Scope: package

My questions are as follows:

1. Is it possible to call one user variable inside the other? If yes, can someone please explain me the code as to how to do it?

2. If not, then, can this be done in a script task and / or SQL Execute task?  If yes, can someone please explain me the code as to how to do it?

Thanks in advance!!