Count A Table With Words In It

I am trying to use Excel to do my manpower allocation and planning. So I have
a column of employees and a row of months. I then put in the project name
that each is working on in a given month.

then at the bottom, I just sum the number of people working on a particular
project in a month and do a simple calculation between the number of
available people and the number who are allocated. This works beautifully IF
each person only works on one project in a month. As we know, this is an
unreleastic assumption!

What I would like is for me to put in multiple project names in a cell and
for the 2nd table to be smart - i.e. if I put in Project A & B for John, then
it should count John as 0.5 for each A & B not 1 for each A&B. Similarly if
John is working on 3 projects, then it should count only 0.33 for each
project John is working on.