There is no function in the Pari system to calculate the Ramifications
groups. Given an irreducible polynomial F with integer coefficients and
a given rational prime p, there are functions in Pari to calculate the
ramification index and inertia degree of all primes in the field
defined by a root of F lying above p. From this you can generally
deduce the ramification in the splitting field. But if the
ramification is wild I don't know of any way to find the higher
ramifications groups using Pari.