Question to svn merge (merge just parts of a diff)

Dear users,

I`m quite new to svn. I would like to know it the following in svn is
possible:

I have in (let`s say Revision 2) a file, that I have changed onetime (I
deleted "B"), with the following content now:
A
C
D

Then, in Revision 3 an automatic update occurs. The new file has the
content:
A
B
E

...that means that some changes, that I made, are overwritten now. But
that should not be.....

A diff between 2 and 3 would show someting like:
A
-C
-D
+B
+E

Is there a possibility to do (for Revision 4) a "svn merge" to get a new
file, that:

* "knows" that B has been deleted before, so it will not be reintegrated
* does not delete C and D (I would like to declare s.th. like: Don`t
delete anything that has been added in a former revision)
* integrates E (as a new entry, that has not been in any former version)

so that a result like:
A
C
D
E

...comes out?
What I mean is: Is it possible to "have a look to a diff" and then
analyze automatically by the system the single-diff parts
to set some rules if the single diff-parts should be integrated or not?

Thank you very much, Kai

-- 
------------------------
Dr. Kai Behncke
Zentrum für Informationsmanagement und virtuelle Lehre
Raum 42/06, Heger-Tor-Wall 12, 49074 Osnabrück
Telefon: +49 (0)541/969-6505
http://www.virtuos.uni-osnabrueck.de