Two articles from the Irish Times you might find interesting:

IRA may allow drugs if it given a cut of profits, Irish Times (March 11, 1998)

Paramilitaries paid by drug dealers - RUC, Irish Times, March 12, 1998 (view from the RUC)

I found the second one especially interesting, reading that a top man from the RUC (the police) (a) differentiates quite clearly between actions of a paramilitary group as such and crimes of individual members and (b) says explicitly that the IRA isn't involved in the same way in drug dealing as the loyalists and the INLA are.

Wolfgang