Currently, you cannot hide your "Friends" list on your userinfo page in the same way you can hide who lists you, and even if you could, this would not stop people from looking at your friends page to determine who you list as a friend. However, what you can do is list everyone who lists you as a friend, then use the Friends Group facility to create some custom groups as follows, which will allow you to hide whose journals you actually read.
You can create a group called "Default View" which you can place the journals that you wish to read into. This will replace your friends page when you are logged into your account. No-one can see this group but you.
Please note that listing everyone as a friend will allow them to view your diary entries marked with security level "Friends". For this reason, it is suggested that before taking this step, you create a seperate group (it's up to you what you call it, but "restricted" seems like a good suggestion) where you can put the names of those users you wish to see posts you would normally mark friends only. You will then need to go through your journal editing the friends only entries and changing the security level setting from "Friends" to "Custom" and tick "Restricted" (or whatever you called your restricted group). Once this is done, you can safely add all those that watch your journal to your friends list.