\sethook and periphs

How to I create a \sethook which points to a periph? (Or, can I?)

I’ve tried \sethook{before}{periph:publisher}{\def\PageBorder{}}, but that didn’t work.

This slide from the recent workshop would suggest that it might be possible, but I’m also wondering if there is a mistake in the syntax on that slide:

Why is there not a {before} or some other position information before the location marker?

Well caught, it should read \sethook{...}{id:GEN}{}

Are there start/end hook-points on periphs? The answer is not yet.

I can see how {start} and {end} would work, but setting a {before} or {after} on a periph seems like it would be ambiguous. Should it occur before the periph definition or before the periph invocation? (e.g. if you set it on {before}{periph:intnt} does it occur just after Malachi 4:6? after the page break? or at the end of the previous periphery in the INT book?)
And if someone puts a {before} hook for the coverfront periphery (contents of the front page), where should that go?

I forgot to say… work around: You can set hooks on stand-alone milestones, and use a changes file to add them wherever you want.