If you want to hide fields from specific users follow the instructions below:

1 - Hit "Customize Form", then click the wrench/screw driver icon next to the field you want to hide.

2 - Once you are on the "Properties" window, click the blue "Data Dictionary" link.

 

3 - See the explanation on the image below:

 

 

Note - If you want to hide the field for more than 1 user you can separate the username by a comma with no spaces (WCTRAIN,DLTRAIN,SCTRAIN,ETC)