Jane10
I've often thought about writing about it GeminiJen and I might yet!
Oh yes, Jane10 please do!
It has been made very plain by the organiser that there is a 'them' and 'us' situation, made all the more sad because only four of the flats are occupied by tenants.
The person organising this sounds very unpleasant; I have visions of a Mrs Bucket but without the unintentional fun.
I'd be inclined to turn down the invitation and at the same time make it plain to the other owners exactly why.
You could, as has been suggested, sit with your posh picnic on that day and see who else is confident enough to join you and ignore her petty party. The grounds are communal so she can't stop you.
I have assumed the organiser is a she, but, of course, could be a he.
Of course, if lockdown has not eased what she/he is proposing is against the rules at the moment. You could point that out to her/him too.