Need help with verticalspreads

Are you saying that you want two Master Pages to be vertically aligned in the Master Page Area of the Pages Panel? That is not possible. Or are you saying rather that you want the pages of the document to be single pages with each page having a Master applied to it? If you're asking for the latter then set the document up as single pages rather than Facing Pages and create a different Master Page for each type of page that you want. When you create a document as single pages (make sure that Facing Pages is unchecked in the New Document Window) then you will note that in the Pages Panel Master Page area each Master Page is only one page. See screen shot below for example:

If your document is already Facing Pages and you want to be able to break up the spreads then first make sure that "Allow Document Pages to Shuffle" is turned on in the Pages Panel pull-down menu. Then go into your Document Setup and uncheck Facing Pages. After you click on OK you will be asked if you want to maintain the number of pages in the spreads and you will say no. Then the pages will flip down into single pages. If you have art or copy that goes across the spreads you will have to split it up before you do this in order to maintain your design. After you do this you will note that any elements such as page numbers or inner and outer margins will have the attributes of the left hand page of the original Master Page. You will have to create a right hand Master that you will then apply to all of the pages that should be right handers using the Apply Master option in the Pages Panel pull-down menu.

If I have missed something in regard to your question please post a screen shot to show exactly what it is you're looking for.