Salesforce.com Bulk trigger

I would like to update the ‘Activity Due Date field’ when the date from another 'Activity Due Date field' changes. All 'Activity Due Date fields’ are related to the same Custom Object called ‘Property’ (see attached) This proposed trigger is performing the same function as a Gantt chart, whereby the cascading task dates change whenever a previous task date changes. Please refer to the attached tasks, showing their predecessors. The Activity Due Dates will be updated as follows: Activity B = Activity A + 1 day Activity C = Activity B + 2 days Activity D = Activity B + 2 days Activity E = Activity B + 2 days Activity F = Activity E + 4 days Activity G = Activity E + 4 days Activity H = Activity G + 1 days Activity I = Activity H + 4 days Activity J = Activity I + 1 days Activity K = Activity J + 1 days Activity L = Activity K + 1 days Activity M = Activity K + 10 days Activity N = Activity K + 11 days Activity O = Activity N + 5 days Activity P = Activity O + 10 days Activity Q = Activity P + 1 days Activity R = Activity Q + 20 days Activity S = Activity R + 10 days Activity T = Activity S + 10 days Activity U = Activity T + 10 days Activity V = Activity U + 10 days Activity Z = Activity V + 22 days Activity A1 = Activity Z + 10 days Activity B1 = Activity A1 + 30 days Activity C1 = Activity K + 10 days Activity D1 = Activity U + 10 days Activity E1 = Activity M + 1 days Activity F1 = Activity V + 10 days Activity G1 = Activity Z + 10 days Activity H1 = Activity A1 + 10 days Activity I1 = Activity B1 + 10 days I have 40 individual ‘Property’ Custom Objects, so I intend to duplicate the Bulk trigger for each Custom Object.