how to make which recipie to run dependant on if the intermediate was cooked or not

We use a program called UMLGraph to generate UML diagrams from
pseudo-code (actually pseudo-Java) this program as a intermediate
product (it leaves the temp file though) produces a .dot file for
input into graphviz (a graph visualization tool) and then graphviz
does the final rendering of the textual description of the UML graph
(it's own little lang) in a number of formats including jpg, gif, svg,
tiff, etc.  Obviously raw graphiv files should also be processable
(namely I am translating a EBNF definition into the DFA that
implements it use a state machine diagram).   Graphiz *requires* that
all input files be called "*.dot" and since we always want SVG output
so that each aeb updates the pseudo-wiki we use for communicating with
client(s) during the design phase of a project (namely every time we
alter the design [and run aeb] the site is fully up to date).

Enough background I need to write two recipes that have the same
target pattern but have different source patterns for example:

%0%.svg: %0%.java
{
   echo It is a UMLGraph file;
}

%0%.svg: %0%.dot
{
   echo It is a raw dot file;
}

How can I write a set of recipes with out cook barfing on it?