add a date-to-date interval

Hi,

I'm sorry, but the addon doesn't have such a feature. 

Currently, we have paid plugin customization and custom addon development services at the gVectors Team. They can assess the work and create it for you. Just contact us via sales[at]gvectors.com email address and send a list of requirements you'd like to have.

Are you saying that there is no already implemented functionality in the participant search filter, for example, to filter participants by age from 20 to 30 years old if the profile has a numeric age field?