Software Deployment

I have to write a cutom action to run an exe silently which in turn calls another msi.
I can directly call the msi as a nested msi as the msi has a dialog which is not getting suppressed by any mean.

If I run the custom action in ExecuteImmediate it wont execute the msi as only one msi execution is allowed in execute.
I tried running it in UI execution after ExecuteAction but somehow custom action is not getting executed. There is no condition for the custom action then also it's not getting executed.

log file says return code 1 for this custom action. can anyone help on this?

thanks,