No way to do that with one text caption.
But about lining up and distributing the text captions: are they all 'oneliners'?
In that case: create the first text caption and put it in the wanted location. Then follow this routine to create the second one:
- duplicate the first text caption with CTRL-D
- use the sequence SHIFT-LEFT and SHIFT-UP: now the two captions are exactly in the same location
- use shortcut key SHIFT-DOWN to move the second caption down until you have the wanted place, and try to remember the number of times you used the shortcut
If you repeat this for each following caption they will all be aligned perfectly and distributed.
If they are not all oneliners, then choose the biggest text caption (in height), co-select all the others and:
- use the right-click menu to resize them all to the same size (Align, Resize to same size) or if you are a click-click user open Window, Align, all buttons you need are there
- use the Align toolbar (Window menu) or the right click menu to align them left
- put the bottom one as low as possible, and use menu or toolbar to distribute them vertically