1. Link them. Sorry, but you either fix start dates for non-linked items as appropriate, or you link them.
2. Put in a delay buffer as a dependency. Insert them as needed between what has happened and what will happen subsequently.
You may also have to split a task. “Paint the walls of the house,” may be split into “Paint the front of the house,” followed by “Weather delay,” followed by, “Pain the north side of the house, ” followed by, “Swarm of locusts,” followed by, “Pain the back of the house.”
Project also permits the addition of subtasks to “Paint the house.” Use insert and the indent button to update a unit task like, “Pain the house,” to include subtasks as described above. When you have finished painting the house, roll-up the task by hitting the minus sign in front.