Track the time and say its "just for your own diligence".
An attitude of acknowledging there is always a clock running and you engage with how you allocate it has, in my experience cuts through this kind of poor teamwork quickly.
You never say they aren't important or you don't have time, you just make it explicit how much time and how often that liberty, which they are always free to take, is being invoked. In a way you value them more by committing your undivided attention.
This response is analogous to when people look at the health information on a snack and think " maybe i ought not eat the whole box in a sitting ". They are still free to do so, but the information makes the responsible and foolish choice more apparent.
At its core is teaching a new level of conscientious relationship with professional engagement. You're helping them grow as a human while maintaining dignity and encouraging a more intentionally sincere and personal relationship.