Task constraint in MS Project

Can any MS Project gurus out there help me with this one. I have a constraint on a summary task (detailed design) that goes like this: No more than 25% of the detailed design may be finished before the high level design is finished. HLD is the only predecessor to detailed design.

I know how to use the lag feature to implement the situation where Task B can start when Task A is 80% complete, but don’t know how to do it for the situation I’ve described above. Is there a way it can be done in MS Project?

Regards,

Richard