Complex sentence: Club Sandwich: those in their 50s or 60s sandwiched between aging parents, adult children and grandchildren, or those in their 30s and 40s, with young children, aging parents and grandparents.
Split into simpler sentences: Club Sandwich: those in their 50s or 60s sandwiched between aging parents, adult children and grandchildren. OR those in their 30s and 40s, with young children, aging parents and grandparents.