How to display the master TOC when using Context help in a merged document

Question

I use Robohelp 10. I have created a large Merged Webhelp project and I have set out the project master with nothing in it other than merged projects place markers.
This is the layout of the generated projects etc.
Generate
          Master.htm
               Redirect.htm  (Home page is a redirect to Project 1 Home Page - not in TOC)
mergedProjects
          Project1
              Home Page.htm
          Project2
               Redirect.htm  (Home page is a redirect to Project 1 Home Page - not in TOC)
          Project3 etc.
                Redirect.htm  (Home page is a redirect to Project 1 Home Page - not in TOC)
I can get the help to work great when I call up the master page, which shows the TOC for the whole project and the default home page. And from the breadcrumb the home link goes to the home page and shows the Main TOC
However when I call a page using context help ID I get a single frame with the selected page. The link to show the TOC shows the TOC but it is the top of the merged project and not the master TOC. The home link in the does display the home page but again the displayed TOC is the one of the current merged project.
The question is :
How can I get the Master TOC to show all the time regardless of what page I call using a context ID or how can I create a link that will take me back to the Master TOC?
I remember when I created a previous help file for chm output I had to modify all the ali files in order for the redirect to work throught the master chm. Surely this is not the case with webhelp?
TonyC

Answer 1

I am sorry that I didn't get back to all you guys that took to answering my very promptly. Unfortunately I was not in a position to answer to the suggestions made. as I was away from my computer which had Robohelp on.
Anyway, I did try a couple of scripts mentioned, but didn't really have any success i achieving what I need to do.
I set up a redirect which redirected to the main home page. I tried setting the home page in a  main sub-project - so the redirect when from any sub project
Generate
     Master-project.htm (Home Page = Help_Welcome.htm)
merged Projects
SubProject1
            [Home Page =  home_redirect.htm (a redirect see below) ]
     SubProject 2
            [Home Page =  home_redirect.htm (a redirect see below) ]
     SubProject 3
            [Home Page =  home_redirect.htm (a redirect see below) ]
home_redirect.htm  (a redirect use by sub-topics)
<!--
   window.location="../../ Help_Welcome.htm ";
//-->
//]]></script>
This setup works fine as long as I call the master page. The TOC is as I would want. However if I call an ID from my application I get the required page to display and I can get the TOC to show. The problem is that the TOC is from the current sub-project and not the master project as I would want.