Concatenate Cells Using Delimiter

I receive multiple worksheets containing transaction data with multiple numbers of row and columns. The data columns contain varying types of information like: price, quantity, location1, location2, loading dock, transaction date, buy/sell, purchaser, seller, currency unit, etc.

I have a need to concatenate into a single cell in a blank column, data from a number of cells in each row -- sometimes two cells, sometimes more. In some instances, I'd like to concatenate data for location1 and location2 with a delimiter like a semicolon-and-a-space to create a cell with: "location1; location2" Or in another instance, I'd like to concatenate multiple cells in a row, like: "location1; price; quantity; transaction date", etc.

I'm looking to create a macro that, with the cursor in a blank cell in a blank row, would open an input box, ask a user to select with the cursor the cells in the row to concatenate and then concatenate them into the blank cell in the row.

Ideally, the macro would populate the entire blank column with the concatenated data for the group of selected cells (from the same columns as in the row where the cells to be concatenated were selected) for each row where there is data. It is also possible that some cells in some rows of the selected columns would contain no data. In that case, I'd be looking to return just the delimiter, like: "location1; ; quantity; transaction date"

Right now, with no macro, I do it by hand like this:

To concatenate into cell I6, the contents of cells A6, B6, G6 and H6, I do a "=CONCATENATE(A6,"; ",B6,"; ",G6,"; ",H6)" in blank cell I6, but I'm looking for a way to do it fast in a macro that would fill in all of Column I.