Nothing. You basically made sure you can not use easy LINQ and whoever came up with that should get a firing for that.
What you can do - best - dependso n the data layer. Yee, LINQ Is not a data access technology, it is C# integrated query, and the specifis depend on the provider (Linq2Sql, entity framework, NHibernate) and you make sure not to give any information.
Anyhow, your problem is that you need to add start and end sql commands - some providers can do that - as well as basically special SQL and that just wll not work.
Best chance would be taking an open source data access provider (NHibernate, Entity Framework) and extending it to allow this functionality.
Otherwise standing in front of the architect and telling him "hey, you wrote the specs- ever thought you have to acutally make sure they are fesible?" is the alternative. THis is really non standard SQL you need here and run of the mill ORM's will not support it without modification.