We have a large base of code that contains several shared projects, solution files, etc in one directory in SVN. We're migrating to Mercurial. I would like to take this opportunity to reorganize our code into several repositories to make cloning for branching have less overhead. I've already successfully converted our repo from SVN to Mercurial while preserving history. My question: how do I break all the different projects into separate repositories while preserving their history?

Here is an example of what our single repository (OurPlatform) currently looks like:

/OurPlatform
---- Core
---- Core.Tests
---- Database
---- Database.Tests
---- CMS
---- CMS.Tests
---- Product1.Domain
---- Product1.Stresstester
---- Product1.Web
---- Product1.Web.Tests
---- Product2.Domain
---- Product2.Stresstester
---- Product2.Web
---- Product2.Web.Tests
==== Product1.sln
==== Product2.sln

All of those are folders containing VS Projects except for the solution files. Product1.sln and Product2.sln both reference all of the other projects. Ideally, I'd like to take each of those folders, and turn them into separate Hg repos, and also add new repos for each project (they would act as parent repos). Then, If someone was going to work on Product1, they would clone the Product1 repo, which contained Product1.sln and subrepo references to ReferenceAssemblies, Core, Core.Tests, Database, Database.Tests, CMS, and CMS.Tests.

So, it's easy to do this by just hg init'ing in the project directories. But can it be done while preserving history? Or is there a better way to arrange this?