You might want to try using cross-references (x-refs). You can insert an x-ref by selecting the word you want to reference in the main text (Cross References panel menu > New Hyperlink Destination). Save as a text anchor (it will fill in with the name of the word if you've selected it). Then, in the text frame that will scroll, from the x-ref panel menu, choose Insert Cross Reference, choose Link to Text Anchor, and choose the anchor from the pull-down menu. You will probably want to click the little pencil next to cross-ref format to format how it will look in the text. Choose Text Anchor Name as the format and remove the quotes around it.
It fills in the name of the anchor for you. You can then put that text frame into a frame and set it to scroll. When you need to update the glossary text, it's a matter of double-clicking on the frame until you've selected the text frame containing the text. You can make any changes, click off, and it's set to scroll again.