In this pic you see the diagram of the tables.

How it works:
In the Project table form, you have a column that is a Lookup to the Subprograms table, when selecting a Subprogram, it associates the Project with that Subprogram by creating a record in a 3rd table called "Project to Subprogram".
A Project can have multiple Subprograms, aka multiple records in the "Project to Subprogram" table.
I want to filter the Projects by using a column that is a Lookup into the Subprogram Title, grabbing all the subprograms basically.
So when selecting a Subprogram in that column, it will show all Projects that have that Subprogram associated with them.
I can`t think of a solution for this, any idea on how can I make this happen?