Adding text from different rows into one column contingent on another row function

Hi Guys,

I want to be able to merge the text from a few rows onto another column based on the text found in the rows next to it.

For example, I want to create a new column for Sizes of a product which should be XXS, XS, S, M, L, XL, XXL

I can do that no problem with the =(&", "&) function but to do it manually for 40,000 different rows is painful. How can I create a function that will check the text of the column next to it, if it is the same text than it will merge it into the function =(&", "&) and if it changes then it will move on to the next row.

See the example attached.

I want the cells in Column H to check the text in Column E. For example, if the text in Column E is the same for 5 rows than it will output whatever text is in Column H with the =(&", "&) function. If it is different, and changes to a different text in Column E than it should create the same output just with the text from the cells in H that correspond to the new text in E.

Please help me out. I have been wrapping my brain on this for hours and can't seem to get it right!