My research leads me to the belief that the Douglas family in Sutherland originated in the Borders, both English and Scottish. Following the Clearances, many sheep farmers were 'imported' to bring expertise to the new occupants of the Highlands, sheep.
Families dispersed across the county to take up their new positions. Thus one brother might be in Farr, on the north coast, and another in Assynt, on the west coast.
The more information you can give about the people you mention, the more chance there is of someone else connecting with your family.
Dates and places of births, deaths and marriages all help to place families.
Professions also help.
'My great-grandmother mother was a Douglas from Montrose' does not give many clues to follow up! But a bit of flesh on the bones makes further research possible. But if we are told who she married, what his profession was and where the children were baptised, then we can get to work.
Maybe it is time to update the information in your profile?