There's no way to create one membership and share with multiple people... BUT you can create a membership that equals the shared membership price and link the billing between the couple or family.
Create a membership:
example 1 - Member A and Member B are husband and wife and you have a couples membership for $280. Create a membership for $140 called "Couples Membership"
example 2 - You have a Family Membership where the first person is $150 and every person after that is $120. Create a Family Membership where the first payment plan is "First Family Member" for $150 and an have a "Family Add-on" for $120.
Link billing to the family members - https://intercom.help/chalk-it-pro/en/articles/9998828-how-do-i-link-one-payment-account-for-multiple-profiles. If they're children, they might be set-up as sub accounts - https://intercom.help/chalk-it-pro/en/articles/9998403-sub-accounts-and-kids-profiles.
Assign the memberships to each family member accordingly.
*There are plenty different scenarios that you can use for this situation. Our recommendation is to create a payment plan accordingly and link billing or create sub accounts for the family, then assign memberships accordingly.