After concatenateing need to get rid of last comma

We have 8 columns. The amount of cells with data in it varies anywhere from one cell to all 8 cells. We would like to combine the data in all 8 with a comma and space in between each one but no commas for those cells that don't have data. We also would like to add an "&" before the last one (replacing the comma).

We used this VBA to add the commas to the end of each individual cell:

Sub AppendToExistingOnRight()
Dim c as range
For each c in Selection
If c.value <> "" Then c.value = c.value & ","
Next
End Sub

We then did concatenate for all 8 cells which pulled it all together into one. We are stuck at how to get rid of the last comma (at the end) and how to replace the second to last comma with the &.

Right now it comes out something like this:

Data 1, Data 2, Data 3, Data 4, Data 5, Data 6, Data 7, Data 8,

We would like it:

Data 1, Data 2, Data 3, Data 4, Data 5, Data 6, Data 7 & Data 8

We would appreciate help with this