Add a person to a smartlist on a Custom Object field update

Hi all,

I'm currently facing a challenge I can't solve alone.

I have created a Custom object on Leads which will be updated every week approximately.

I would like to add people to a specific Smart List according to what a certain field in the Custom Object contains. Since the Custom Object can be updated, it needs to check the condition evey time the Custom Object is updated.

Is there any way to do so?

Thanks in advance!