Cavatelli Pasta with Lobster, Spring Peas, and Mascarpone

In 10- to 12-quart pot, bring salted water to boil. Plunge in 2 lobsters headfirst, then boil, covered, 10 (for 1 1/4-pound lobsters) to 11 minutes (for 1 1/2-pound lobsters) from time they enter water. Transfer with tongs to sink to drain. Return water to boil, and cook remaining lobsters in same manner. When lobsters are cool enough to handle, remove meat from tails and claws. Discard or reserve for another use tomalley, any roe, and shells, and wipe off any coagulated white albumin from meat. Cut meat into 3/4-inch pieces and chill, covered, at least 1 hour.