If the whole house if fit, will you have a better chance? If you all share the lifestyle, will it lead many choices made on a daily basis from meals, bed time, grocery shopping, entertainment and leisure.
Yes, your 10 year old or your spouse may not match up even if doing the exact thing you do to train but with some thought could you make it very close?
Here are some ideas:
-swim in Swim Training Center next to each other working appropriate paces
-run on treadmills next to each other
-bike on trainers
-swim a workout calculated for the faster person to do 300 and the slower do 250, ending at the same time
-run or bike out and backs to keep you in the same area
-faster runner run while slower ride ElliptiGO
-lift weights together setting up routine, reps and exercises to fit each
-indoor rock climb and challenge appropriately
-faster swimmer swims while slower SUPs
-slower biker can draft behind
-person not doing as much distance can do the end of the workout for appropriate distance, also adding motivation for longer workout person
-pick cross training activity both can do like a sport like tennis, soccer, basketball, etc
Just imagine how you will help each other. Just imagine how you will pass this lifestyle down to the next generation.