It is a little difficult to decipher what the problem is or what you are looking for but I will give this one a shot. From what you wrote it seems you are using a combo box and when you drop it down it displays more than the first field of the table/query but what you want is only the first field. If that is correct this should fix it.
Open the form in design view and right click the combo box and pick properties. Click on the format tab and look in the row titled Column Count. From yourexample you probably have a number in there ? something like a 5 ? whatever it is change it to a one. Save and close the form. Now the combo box will display the first field in the table/query and not display the others.
Erwin