Configure BizTalk Database with DNS alias

Hi, 

I need to build a BizTalk setup for Production and DR. We have two WNLB BizTalk AppServers and SqlCluster in Production and DR is standalone (only with one application server and the database -DR is not clustered)

Now, the idea is to implement the logshipping capabilities between production and DR for above topology. Now I wanted to know whether logshipping can be implemented for the topology of two production servers and one DR server. (Correct me If I am wrong)

I have gone through below Microsoft recommendations, still I have some doubts in mind. 

http://msdn.microsoft.com/en-us/library/aa546765%28BTS.10%29.aspx

http://msdn.microsoft.com/en-us/library/aa560961(v=bts.10).aspx

http://msdn.microsoft.com/en-us/library/aa561125(v=bts.10).aspx

I heard that configuring both production and DR sites under one BizTalk group and using DNS alias names for BizTalk databases on both sites(Prod and DR) will make job simpler, I am not sure how to configure biztalk databases with DNS aliases. 

Now, we are using SQL Cluser name for production, and the DR has its own sql server name. Pl. note that both production and DR are on different locations under one domain. Also I wanted to know how to fail over from production to DR an DR to production. 

Please help.

Thanks.

KP.