All literature seems to agree that Peter(s) is a Sept name for the Clan MacGregor.
I have found a referece which claims that the
“14th, Gregor More, of Breakly, of whose third son Malcolm of Inverey, Braemar, are descended several good families in Braemar, and adjoining counties, to this day; but, during the general persecution, they lost their lands, and name, and assumed the different names of Ogilvy, Gordon and Peter, (of whom are all the Peters of the Shires of Aberdeen, Angus, etc.)”
I have traced the name to the St Vigeans area of Angus around 1720-40 and found only one connection in the form of a gravestone inscription at Inverkeillor which links the names
1746 James Peter husband was to Elizabeth Rait in Colliston Mill he died 10 July 1746 aged 34 four children first James,William,Isoble & John; three of them is yet in life. Isoble lyes……1746 4y .He was leg(ume) artus apueribus natus ab Malcolm tertio filio Gregaris xiv Princeps de Tribus Gregor & tenant on Kirkton of Inverkeillor
Can anyone help make a more secure connection or add to the links?