Group build question

I have an idea for a non-denominational (more than one catagory of model) group build, it seems like most group builds get started in one catagory like aircraft, armor etc. How would you suggest I do this, multiple posts (one in each) seems confusing but picking one would likely leave out the other groups.

My thought was to do a "got a new job" group build, models depicting equipment after their original owner has retired it so it could include topics rangeing from military vehicles under new colors or completely new duties, so an Isreali Sherman, a duece and a half rebuilt into a phone utility truck, a B-17 converted to Fire Bomber, a PT boat converted to a Customs boat or a P-51 Mustang air racer would all be acceptable.


So how would you advise I approach this?

Thanks