...to answer my own question, this may help someone else.
although I did not find a way to limit the market locator to only one market based on "Market's name contains value in file", I have achieved making sure (hopefully), that the undesired markets are not caught by trigger even if they get activated (despite they should not, due to import file filter).
by adding an imported value within the import file (mind that separator must be tab):
["dynamo kiev v fc minaj/Over/Under 0.5 Goals"]"Over 0.5 Goals" "Over0.5Goals"
imported value can be then used within a trigger condition and be compared against selection name, note that the imported value must be in the exact format as sel_name:
selection's trigger expression imported_1 is equal to sel_name
I am going to monitor this approach further and will post here if I find any more issues.
BR,
Miro