M:N relationship column multiadd

Hi there,
first of all thanks for developing this great tool.
I implemented Xataface for a Database holding Users and Courses they have visited.
Now there is a m:n relation between these two tables. Therefor i created a third table. Then i created a relationships.ini and so on like it is described in the Documentation. Is all working fine. But now i would like to customize the Users tab at the Courses Page in that way that i'am able to add many users with an advmultiselect list. Is there a way to do that? Now i'm just able to add one after each other with the add existing record tab.
Best Regards Jakob
first of all thanks for developing this great tool.
I implemented Xataface for a Database holding Users and Courses they have visited.
Now there is a m:n relation between these two tables. Therefor i created a third table. Then i created a relationships.ini and so on like it is described in the Documentation. Is all working fine. But now i would like to customize the Users tab at the Courses Page in that way that i'am able to add many users with an advmultiselect list. Is there a way to do that? Now i'm just able to add one after each other with the add existing record tab.
Best Regards Jakob