Getting all related records from relationship w/o constants

I have one important question: 
Can I add some string or other value to the lefthandside of  a
relationship in order to get a relation to all records? The problem is
tricky as the relation in question is based on name and not a constant
like "1". 
Could I perhaps make a constant relation and build 2 popups from each
relation and then somehow set a third popup to the values from either of
those,  if the filter field contains a value? Any ideas on how to do
value list source switching like that? Just get me started....

Background: I have built a relationship based on the value of the Global
"NameSearch" in my contacts.fp5 DB to a NameIndex field, storing on
multiple lines the 1st, 1st and 2nd, and so on, character from the
namefield value***, both the latter in my Individuals.fp5 DB. 
If the user write a string I can then choose the name from a dynamic
pop-uplist, which sets the connected field "related_ID" to the ID of the
connected Individual. 
However, I'd like all names to display if the user types nothing, so I
thought that adding "*" (sans "") as a default value would do the trick,
but that gives no results. Does putting characters like "*" only work in
Finds? Is what I want totally impossible?