Fill cells with cell above

I have a spreadsheet that has multi rows of data that I need to combine into on row with reference to it reference number cell.

The amount of data entries between the reference columns can vary greatly from one to twenty.

Now that I have confused you greatly here is a sample of what I have and need.

Have now
123456 1st line of text
---------2nd line of text
---------3rd line of text
---------4th line of text
234567 1st line of text
---------2nd line of text
987664 1st line of text
999666 1st line of text
----------2nd line of text
---------3rd line of text
---------4th line of text

Need
123456 1st line of text 2nd line of text 3rd line of text 4th line of text




234567 1st line of text 2nd line of text

987664 1st line of text
999666 1st line of text 2nd line of text 3rd line of text 4th line of text

Thanks for the help.