Calculating Quarterly Dates by Months not Days

[Artboy34]

I have a spreadsheet that I use to keep track of quarterly reports, generated off of a different fixed date for each series of dates. Currently, I am calculating the dates by the number of days (90, 180, 270, etc.), but this doesn't allow for the extra 5 (or in this year's case, 6) days in the calendar.

Is there a month function in the formulas that can calculate this? For example, if the fixed date is 10/19/2015, I would need to populate the cells with 01/19/2016, 4/19/2016, and 7/19/2016. Please note that I do not need to calculate the difference between two dates (there seem to be a million posts about that), but I need to populate cells with quarterly dates based off of the fixed date.

Thanks for any help!