"Strangers" holding baby

Does anyone else's baby have stranger anxiety and what did you do to help them? 
Our daughter is 4 months old and cries if anyone besides me or my husband hold her. 
Today we kept letting his mom and brother try to hold her for a couple mins at a time and she just curled that lower lip and cried her eyes out immediately! We thought she just needed to keep practicing but she was hysterical and by the end of the night if they even just talked to her she'd start crying. It hurts my heart to hear her cry/ scream so much, at the same time I want her to trust them- grandma especially.
She's only seen them about 3 or 4 times ever, since we all live far from each other. 
Has anyone been in the same situation and what did you do? Should we just not let anyone hold her, or would you say it's beneficial to get used to being held by others slowly? 
Any advice would be great! 
Side note: we take her out all the time and she sees people in public and friends of ours. She loves hanging out, it's just when anyone tries to hold her that she flips. Today was just especially hard because it's family.