I'm not completely clear on what it is you're trying to do, but it
sounds like some custom ticket validation rules. In which case your
best course of action is to do it through a plugin, probably one that
implements the ITicketManipulator interface. See
http://trac.edgewall.org/wiki/TracDev/PluginDevelopment as a starting
point.
Sounds simple enough but I'm still not entirely clear what you want to
do--that is, what do you mean by "consistent with the selected
component"?
Jeff Hammel
The Open Planning Project
http://trac-hacks.org/wiki/k0s
IRC: jhammel, k0s