You might be able to use the object screen x() and y() commands like this:
Rem Start of code
Rem Replace number of objects with number of objects
DIM obselect(number of objects)
blah...
blah...
Mouseover(1)
blah...
blah...
FUNCTION mouseover(Object Number)
IF MOUSEX() > OBJECT SCREEN X(Object Number) and MOUSEX() < OBJECT SCREEN X(Object Number) + OBJECT SIZE X(Object Number) and MOUSEY() > OBJECT SCREEN Y(Object Number) and MOUSEY() < OBJECT SCREEN Y(Object Number) + OBJECT SIZE Y(Object Number)
obselect(Object Number) = 1
Else obselect(Object Number) = 0
ENDIF
ENDFUNCTION
Don't know if it will work though. Never tried it.
"All programmers are playwrights and all computers are lousy actors."
-Anon.