auto complete tags / custom dictionary?

I use LibreOffice Calc to save information of items in an archive, and i would like to use some sort of tag system to auto complete tags if a new item added and needs to be tagged.

i have colums named titel, typ, creator, tags etc. and every row is an item. I add the tags comma separated in appropriate cell.

I have a long list of tags (ca. 6000 Words) from older projects and i tried to add it at the very end of Tags Colum -one cell in row for each word-. i expected to auto complete function will do it. but obviously it auto completes just the first word/tag.

how can i achive that individuall words auto completed? Its important for the consistency of tags.

Thank you very much.