Hi, Michael,
You can use the EQ field with the \o switch (o for "overstrike"). For the
example you gave, the field code would be
{ EQ \o(p,^) }
Since the ^ character (formal name: circumflex) is a little too low, you
should select it in the field code, go to Format > Font > Character Spacing,
and set the position to "raised" by 2 or 3 points.
The space after the closing parenthesis displays in the field result. If you
will want another character to follow immediately after the p, delete the
last space from the field code.
Once you've created a field the way you want it, assign it to an AutoText or
AutoCorrect entry.