Combining multiple rows based on a certain word

I have a text document that I had copied into excel to try and manipulate the data. When copying the document into excel as expected it created a row for each line of text i had in my text document. I posted an example of what the text currently looks like in excel. Basically I want to combine all the text that belongs to each of the BEGIN. So for this example i only want to have 3 cells and for the first cell i want it to say ,BEGIN test smith alex smith bob reynolds in cell 1. and then the 2nd cell will have ,BEGIN ron smith bob hill bill reynolds. and so on. I have tried everything I can think of but some reason can not get it combine the way i want it to. I have run out of ideas. Any help is appreciated.

,BEGIN
test smith
alex smith
bob reynolds
,BEGIN
ron smith
bob hill
bill reynolds
,BEGIN
sponge bob
patrick star

Assuming that data is in column A, beginning in cell A1, then you can use this formula in B1:

=IF(A1=",BEGIN",A1&" "&A2&" "&A3&" "&A4,"")

Copy this down as far as you need to.

Hope this helps.

Pete

Thanks for your help that worked!