Yea - time (PERIOD) is one of the biggest challenges in peoples lives now.
I think in regards to relationships the best way to handle it is to all sit down and just acknowledge it together as a family.
Acknowledge that it's a potential problem ( because it is) and all shake hands on an agreement that you will ALL do your best - acknowledging the difficulty - to work TOGETHER to make the best use of it you can. At the same time acknowledge that it may happen that someone feels they are getting the short end of the stick and that IF that happens ALL agree to sit down and talk about it and see how much is real, how much is perception, and what we can ALL do to handle either/both of those sides.
It's really quite doable but it takes commitment and openness.