By default all doors and buttons pulled from the sideline are tagged as "A" and will interact with each other that way. To change what door the button will open, right-click on the door and choose "TAG >". You can then choose a different letter, up to H. Now right-click the button you want to open that door and set it to the same letter as you set the door to. Now when you step on the button, it should open all doors with the matching letter.

An issue that may come up is if you have multiple buttons. If there are multiple buttons with the same letter, all of them need to be pressed, either by the player, or by other objects, in order to open all the doors with the same letter. This is to allow for multi-button-required door opening puzzles.