You may be misunderstanding what tab objects are used for. Basically, they are used to display different subsets of information about the parent record. So in your case, where you are looking at a member record, each tab will contain information relating to that member. That information may be from the member record itself or from related records.
You therefore cannot display an unrelated visitor record on a tab on a member layout. This makes sense because FileMaker Pro doesn't know which visitor record you might be wanting to display.
The only exception here is that if you wanted to display a portal of perhaps ALL visitor records, you could do that by creating a cartesian (cross) join relationship from th member table to the visitor table.
So what is it you are trying to display and why? Try to provide concrete example to explain yourself.
Thanks for the reply. I suspected what you said was true when I posted the question. So, I can quit trying to get it to work .... :smileysurprised:
As a work around, I placed a 'tab like' button at the end of the tabs which takes the user to a layout that has a button / tab to return to the original layout when finished. Seems to work well.