The Susans and the Simons

Having two Susans and 2 or 3 Simons in the family is a bit of a problem. In both speaking and in writing how do we know which one we are referring to? Context eventually bails us out of course but it would be nice to have more clarity from the beginning.

The Simons are easy: There's Vonnie's Simon, Tracy's Simon and George's Simon (though we haven't seen that Simon for a while).

But the Susans seem to be insoluble. "Paul's Susan" is not too bad but Paul does after all have two Susans: His wife and his sister. But that is not really a problem. When we say "Paul's Susan" everybody understands that the Susan concerned is his wife.

So how to we refer to Paul's sister? We could say "Russell's Susan" but that would not feel right as she was "our" Susan long before she was Russell's. Not that there is any disrespect to Russell in that. His devotion to Suzy is all we could ask. Suzy is precious to all her family so her having a husband who also regards her that way is a great relief. So we could refer to her by her married surname but who uses surnames in referring to family members?

The only other option is referrring to her as "Twinny Susan" and that sounds a bit wet. Definitely an insoluble problem. I think I usually refer to her as "Suzy" but not everyone else does or wishes to.