I don't think this is possible, however I would continue to seek advice from other more knowledgeable people on the forum tonight.
There are however some workarounds. Coxmacro, let you store the position of various models on a map and then load them again after you have restarted city of heros.
I am also working on something similar which allows you to specify crowds of models and/or costumes, and subsequently reload them.
I'll have my little feature available at some point in the next week or two, and will be make sure to post on the forum