How to repeat one or two modules after every five posts in joomla blog? - Joomla! Forum - community, help and support

hi,
i'm trying customize joomla blog such 2 custom modules showing after every 5 posts in category blog layout. i'm using protostar template. i'm willing work 1 custom module if 2 impossible. appreciate help.
thanks.

code: select all

<div class="items-leading clearfix">
   <div class="leading-0>post 1</div>
   <div class="leading-1>post 2</div>
   <div class="leading-2>post 3</div>
   <div class="leading-3>post 4</div>
   <div class="leading-4>post 5</div>
   <div class="cust-mod-1>custom module 1</div>
   <div class="leading-5>post 6</div>
   <div class="leading-6>post 7</div>
   <div class="leading-7>post 8</div>
   <div class="leading-8>post 9</div>
   <div class="leading-9>post 10</div>
   <div class="cust-mod-2>custom module 2</div>
   <div class="leading-10>post 11</div>
   <div class="leading-11>post 12</div>
   <div class="leading-12>post 13</div>
   <div class="leading-13>post 14</div>
   <div class="leading-14>post 15</div>
   <div class="cust-mod-1>custom module 1</div>
   <div class="leading-15>post 16</div>
   <div class="leading-16>post 17</div>
   <div class="leading-17>post 18</div>
   <div class="leading-18>post 19</div>
   <div class="leading-19>post 20</div>
   <div class="cust-mod-2>custom module 2</div>
   ...
</div>


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