You can run
self.jQuery('[id="<action_name>"]')
.add('[id="<action_name>_bottom"]')
.show();
to show buttons on forms and
self.jQuery('[id="<action_name>"]')
.add('[id="<action_name>_bottom"]')
.hide();
to hide buttons on forms, in Client Scripts or UI Policy scripts, but it will only work in Core UI, which is kinda' phased out.
Therefore I suggest NOT going down this road and implementing a solution that better fits the paradigm; e.g. make the UI Action a client one and have it 1st change the state according to what is right for that button (even if the user previously selected some other state) and only after that submit the form.
So even if a user 1st selects (say) On Hold as state, but presses the Close button, the UI Action would 1st switch state to Closed Completed and submit the form afterwards.
You could add in a check whether the state has been changed from the one (with which the form has been) loaded and warn the user that the previous state selection will be discarded - to make it more fool proof.
Utilizing a display business rule that stores the original state value on the scratchpad and regular UI Action client scripting you can come up to a solution that will also work in Next Exp.
