You invite only friends that you really want should be there from beginning to end. If you would LIKE to sit by their simcha all night, then they want to sit by your simcha all night.
Other friends just come and say mazel tov and hang around a little.
I attend MANY non-family simchas a year(neighbors, work related, husbands friends, old aquaintances), but only a few minutes each.
The only meals I sit down to is immediate family or if my aunt marries off.