Bulk Rename Utility

Hi new here and not sure of correct terms but will attempt to explain what I am trying to do. I have several photos ..jpg files. they are named like this
_angie_ ff.jpg
Bill aa.jpg
bill aa1.jpg
Bill aa2.jpg
Bill kk.jpg
Carol ff.jpg
Carol ff1.jpg
Carol gg12.jpg
denis hh.jpg
denis ii4.jpg

I would like them to be change to this example
_angie_ 1.jpg
Bill 1.jpg
Bill 2.jpg
Bill 3.jpg
bill 1.jpg
Carol 1.jpg
Carol 2.jpg
Carol 3.jpg
denis 1.jpg
denis 2.jpg

or
_angie_ a.jpg
Bill a.jpg
Bill b.jpg
Bill c.jpg
Bill d.jpg
Carol a.jpg
Carol b.jpg
carol c.jpg
denis a.jpg
denis b.jpg

There is a few thousand photos all in one folder and the eventual idea is to produce a movie clip (no sound just continous slide show in avi format) and it is important to keep each persons photos together. At the moment when I produce a movie clip they are coming up in random order and some photos not included at all.

Please help

Hoozadoctor