How to redirect button that is inside Html.BeginForm - asp.net-mvc

Question

I have this View which displays 3 text boxes and a drop down list for displaying nationalities. The form itself works just fine, posts back to the controller and nothing is wrong. However what i want is, say a nationality is not present in the drop down and a user clicks a button which would redirect to a different page where they can add a nationality. Here is what i have so far:
#model WebApp.Models.ViewModels.AddPersonViewModel
<div class="container card">
#using (Html.BeginForm("AddPersonPost", "Persons", FormMethod.Post))
{
<form>
<div class="form-row">
<div class="col">
#Html.TextBoxFor(m => m.PersonModel.Name, new { #class = "form-control", #placeholder = "Name" })
</div>
<div class="col">
#Html.TextBoxFor(m => m.PersonModel.Relationship, new { #class = "form-control", #placeholder = "Relationship" })
</div>
<div class="col">
#Html.TextBoxFor(m => m.PersonModel.Comment, new { #class = "form-control", #placeholder = "Comment" })
</div>
<div class="col dropdown show">
#Html.DropDownListFor(m => m.PersonModel.Nationality, Model.NationalityList)
<input type="submit" class="btn-sm btn-primary mt-1" value="Add Nationality" onclick="window.location='#Url.Action("GetAll", "Persons")'">
</div>
</div>
<div class="m-sm-2">
<input type="submit" class="btn-sm btn-primary" value="Add Person">
</div>
</form>
}
</div>
I have tried the redirect option but when i click the button to add nationality it keeps going to the Action in the BeginForm, not to the intended Action in the button. So i was wondering 1. is this good practice to do what i am attempting to do? 2. How to go about it? Any help is appreciated.