There is not a way to filter a multi select field type.
It is possible, however, to have a many to many relationship where
One Company has many Contacts
One Company has many Pilot projects
One Contact has Many
Pilot Project Contact AssignmentsOne Pilot Project has Many
Pilot Project Contact Assignments
The
Pilot Project Contact Assignments table is the "join" table for the
many to many relationship. That drop down of Contacts can be filtered for just the Contacts for that company.