[p4] re-integrate post roll-back

[Andrew Houghton]

Thanks to tech note #14, I managed to roll back a disastrous  
integration of our main branch into a very long-running dev branch --  
I calmly accepted a wide range of merges that, in retrospect, I  
should have realized were insane.

But now I'd like to re-integrate, and do it carefully -- the original  
problem was partially caused by waiting too long between  
integrations, so this time I'd like to do it in smaller time slices.   
Ideally, I'd like a way to integrate code from the main branch at a  
particular point in time into the dev branch as it now stands; i.e.,

p4 integrate -b devbranch @<some change number>
...

p4 integrate -b devbranch @<some larger change number>
...

p4 integrate -b devbranch @<some even larger change number>
...

p4 integrate -b devbranch
...

.. the problem being that I can't see how to do that, given that the  
devbranch believes it's already integrated those changes (a naive use  
of -f and -s doesn't seem to do what I want).

Hopefully that made sense.

Any hints?

Thanks,

Andrew