Help with network security on a shared DSN or ODC

Hi. I am having problems understanding how to apply correct security on a network level DSN or ODC for Excel users:

I have a group of users who need to use a connection (dsn or odc or you tell me) in a network folder location and get a table (or sql statement) back from our sql server. I have created a odc using a sql login info and put it in the network folder and gave the group "read & execute" permissions but they can't open the connection in excel due to permissions but if I add "read" rights then they can use the connection but also open the file in notepad and see the username as password and I can't have that either. How can I allow them to use the connection in Excel but not to open the file up to see the authentication and sql statment in the file?

Thank you!