If I understood your question correctly, you're trying to limit the amount of records displaying in a tree view.
This topic might help you: https://stackoverflow.com/questions/36887942/odoo-8-tree-view-limit-parameter-not-working

You set a counter variable for t-foreach="" and and give condition inside that.

Break your page if variable value is certain.

For Example

<t t-set="i" t-value="1"/>
<tr t-foreach="o.order_line" t-as="l">
     <!--Check Condition and break-->
    <td> <span t-esc="i"/></td>
    <t t-set="i" t-value="i+1"/>
</tr>

All the Best !!!