Master Site includes Sites a & b if found.
IE4 and above use <A HREF="ms-its:filename.chm::/topic.htm">
eg. ms-its:SiteA.chm::/Index_a.htm
IE3 and above use <A HREF="mk:@MSITStore:filename.chm::/topic.htm">
eg. mk:@MSITStore:SiteA.chm::/Index_a.htm
This also appears to work under IE4 <A HREF="filename.chm::/topic.htm">
eg. SiteA.chm::/Index_a.htm
NOTE: The above don't work on my uncompressed web sites.
Jump to Bookmarks in SiteA
mk:@MSITStore:SiteA.chm::/WEB_a/web_a.htm#BookMark_A1
mk:@MSITStore:SiteA.chm::/WEB_a/web_a.htm#BookMark
A2 (contains spaces)
mk:@MSITStore:SiteA.chm::/WEB_a/web_a.htm#BookMark_A3