I'm assuming you want to start the "temporary" footnote counter at zero (to get alphabetic "numbers" starting with "a", "b", ...) and, when the paragraph is completed, resume ordinary, i.e., arabic footnote numbering with the number you left off with before you switched temporarily to alphabetic footnote "numbering". If this understanding is correct, here's a solution:
... % text preceding the crucial paragraph(s)
... % text of the the crucial paragraph(s), including footnotes
... % remainder of document, including footnotes
Note the blank lines, which serve to create paragraph breaks.