It'd be a drop in the ocean, anyway.
Almost all transmission is in schools, other crowded workplaces and then immediate households not wider family mixing.
I mean most working people only have time to see their extended family on the odd occasion, once a month or something. If we're talking retired granny goes to see retired granny friend, yes, that could be frequent, but they're less likely to be catching it and spreading it anywhere else anyway.
I can't see the modelling showing this would make hardly any difference.