mutually exclusive group of options

Hi

I've encountered a problem and don't know how to resolve it. I'm developing a commandline tool which can use either of two shared libraries (.so in short) but only one of those at a time. Furthermore, both .so require different options which are available (meaningful) only if the corresponding .so is chosen. For example:

 scan --init   --dir1=... --dir2=... ; create an own scanning process

or

 scan --attach --address=... ; attach to a daemon

(I hope it is clearer a little bit now what I'm talking about.)

I know I can specify "init" and "attach" as mutually exclusive group options but I don't know how to induce gengetopt to allow dir options only if --init is given and --address if --attach is given. 

Any ideas? Thanks in advance

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Papp, Gyozo