Just an example:
Res markernames are : "Resbase" and "ResStart"
West markernames are : "Westbase" and "Wstart"
Write an init.sqs with this
?(side player == EAST) : "Westbase" setmarkertype "empty";"Wstart" setmarkertype "empty"
?(side player == WEST) : "Resbase" setmarkertype "empty";"Resstart" setmarkertype "empty"
Now the West won't see Resmarkers and Resistance won't see the Westmarkers
About the briefing : Use a MP briefing template, here is one
http://www.ofpec.com/includes/download2.php?id=15