Modules & VBA :: Multiple Field Entry Separated By Comma

I would like update a table column values separated by ; For example

1. ColumA has no data, I want to do an update and place a comma at the end
2. If ColumA has already value do not delete add new valued at the end where ; if found.

My start attempt as follow:

Code:
qry_test= "UPDATE Table1 SET ColumA =" & "Enter Entered ;" & & _
" WHERE ID=" & 1
Set RS = cnnDB.Execute(qry_test)

What do I need to do to add more stuff where ; is found without delete existing value if values exist.