Execute Multiple Request with Key Attribute Collection

Hi,

I am using Execute Multiple Request with Key Attribute Collection to bulk Upsert in CRM. I have a question regarding the KeyAttributeCollection side of things. I want to be able to the following type of record comparison:

The bold texts are attributes in CRM.

if(accountnumber = customerid[i]) then update else if (prospcustid = glaccid) then update else insert the record.

How do I implement the above logic by using the KeyAttributeCollection class? I know you can add attributes to the AttributeCollection but, is there a way I can do record comparison like the above?

Thanks,

Shishir