Ah -- thanks for the clarification. Yes, combining them into a single <text> element is the most straightforward solution in most cases. Otherwise, you absolutely *can* position elements relative to each other according to their size and position:
<trial mytrial>
/ stimulusframes = [1=a,b,c,d]
/ validresponse = (57)
</trial>
<text a>
/ items = ("Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.")
/ size = (40%, 20%)
/ position = (50%, 10%)
/ txbgcolor = (red)
/ hjustify = left
/ vjustify = center
/ halign = center
/ valign = top
</text>
<text b>
/ items = ("Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.")
/ size = (40%, 20%)
/ position = (50%, text.a.vposition+text.a.height)
/ txbgcolor = (green)
/ hjustify = left
/ vjustify = center
/ halign = center
/ valign = top
</text>
<text c>
/ items = ("Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.")
/ size = (40%, 20%)
/ position = (50%, text.b.vposition+text.b.height)
/ txbgcolor = (blue)
/ hjustify = left
/ vjustify = center
/ halign = center
/ valign = top
</text>
<text d>
/ items = ("Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.")
/ size = (40%, 20%)
/ position = (50%, text.c.vposition+text.c.height)
/ txbgcolor = (yellow)
/ hjustify = left
/ vjustify = center
/ halign = center
/ valign = top
</text>