Both documents are odt documents but created with different formating. When I try to attach the cover pages it forces the following document to change margins, etc.
Please, edit your question following these guidelines.
Where your cover pages created with a specific page style? Maybe same name with different settings?
If you didn’t, do it with a manual page break between covers and main body so that you can swith to another page style.
How do you “attach” 2 cover pages?