Page margins - individual settings ?

Hi there,

with "Format -> Page settings " you can set the values for page margins left, right, top, bottom.
In the case you choosed there under "Page size" the checkbox "two sided":
If the value for the left margin of odd pages is changed, the value for the right margin of even pages is connected to that and changes automatically.
(By the way: The values for top/bottom margins of odd and even pages are not automatically connected ! Why this difference ?)
This behaviour is in most cases useful and comfortable.
BUT:
For several reasons (- it would take to much space to explain here -) I would like to set the values for left and right margins individually different for odd and even pages.
Is there a way to do so (as it is possible for top/bottom margins) ?
(If yes, I highly appreciate any help. If no, I have to think about a workaround and do a lot of work on my current score ....)

Thanks to you all,

Ulf