Link Primary Key to two fields in second table

I have a "People" table that I would link to an "Orders" table. The People
table has a record for each individual. A record in the orders table will
have multiple "People" in it (e.g., Person Placing the Order, Technical
Contact, Budget Officer, etc.). I would like to link the Primary Key of the
"People" table (personID) to multiple fields in the orders table and enforce
referential integrity. Access and SQL Server both disallow this. Is there a
way around this? Any thoughts are appreciated.