Aim Your Emails in the Right Direction
Instead of sending emails blindly to each of your subscribers, filter your contact lists using segmentation

Communicate, Interact, and Transact with Customers
Create and save your filters to identify your customers. Edit saved segments and changes will reflect wherever you used it at once
Segment my selected list(s) - Allows you to filter your subscribers who match certain conditions.
Every custom field can be used for filtering contacts. You can create highly customizable segments depending upon your data
Design complex filters by combining multiple criteria using AND/OR conditions
For example - 'doctors' living in a 'city' and have purchased a 'product'
At the time of creating the segmentation rule, there exist some contacts in chosen contact lists.
If you select this option, new entries in the selected contact lists will be checked for this.
Apply on updates in contacts If you select this option then the system will check if a contact is qualified for this segmentation when there will be some old contacts.
You have the power in your hands.
Instead of applying segmentation on every action taken on a contact, you can specify them
Apply similar segmentation on more than one contact list at the same time. This will save your time in building similar segmentation over multiple lists one by one
In this instance, you'll have to update your segmentation many times or perhaps create a new automation.
When segmentation is employed in several campaigns and automation, the task multiplies.
Multi-List Segmentation can easily handle this use case. All "you" have to do is modify the Multi List Segmentation by adding or removing contact lists.
In a quick view, you can see contact lists have been added to a segmentation, the contacts have been qualified from each contact list, and suitable actions have been taken.