There is currently no way to lock/unlock a door, or turn on/off a forcefield or any thing of that sort. You can, however, with certain interactables, such as the Door - Cardassian 01 "detail" simulate doors. You would do it the same way to generate enemies - you just layer events together.
So, for example, for enemies after an asteroid:
Dialog Box for Mission Info -> Go to Marker (optional) -> Interact with Object -> Dialog for Text (Optional) -> Kill Enemies
This will cause enemies to appear after you've interacted with the object, and, optionally, been given an alert that enemies are appearing, and then you will have to defeat them to move on.
For a door, you'd do something like:
Dialog Box -> Go to Marker -> Interact with Object (A console) -> Dialog Box -> Interact with Object (The door) -> Map Transfer
Edit for Clarification:
Keep in mind, certain door types automatically open and close, so this will take some testing to determine what kind of door is useful for 'fake' doors like this. I haven't tested them all, so I do not have a list handy for this sort of gimmick.