I have a table called Servers with a Primary key of Server_ID; a table called
Modems with a primary key of Modem_ID, and a table called Server_HDD with a
primary key of Server_HDD_ID.

Both the Modems and Server_HDD tables have a Number field called Server_ID.
I then have a One-to-Many relationship from the Server.server_ID to
modem.server_ID, and another from server.server_ID to Server_HDD.Server_ID.

The problem is when I create a query. I can add one of the tables to the
query, but if I add them both, the query is blank. Can you not have two
tables share the same ID in one table?