You don't need different repositories for you to separate the different projects or workstreams. Furthermore, you are creating unnecessary additional workflows when it comes to deployments for example.
In my view, you can still achieve your workflow with a single repository. What you need is a code branching strategy, such as Git Flow
Which makes sense since ...
The reason vhost wasn't working for me is because our sitecore implementation is behind a reverse proxy. Vhost doesn't support being behind a reverse proxy at the moment.
Github vhost issue
With a simple modification to the package, you can modify vhost to support reverse proxies.
Based on the question, I assume that you are using Sitecore Experience Accelerator (SXA) with JSS. I had the same issue when I first tried the Single JSS APP for Multisites.
I have documented everything at my blog here: Sitecore-jss one to many
The main reason this is occurring is because the URL for your layoutservice is resolving to Site A. So, when the ...
Follow below steps :-
Create different folder items for each sites pages
Add/enable the SiteDefinition.config file and add site entry,
<site name="MyOnline" patch:before="site[@name='website']" hostname="mvcsitecoredemo" virtualFolder="/" physicalFolder="/" rootPath="/sitecore/content/MyOnline"...